diff --git a/Classes/PHPExcel/Worksheet.php b/Classes/PHPExcel/Worksheet.php
index 0493b6b..f932022 100644
--- a/Classes/PHPExcel/Worksheet.php
+++ b/Classes/PHPExcel/Worksheet.php
@@ -304,6 +304,20 @@ class PHPExcel_Worksheet implements PHPExcel_IComparable
 	 */
 	private $_tabColor;
 
+	/**
+	 * Dirty flag
+	 *
+	 * @var boolean
+	 */
+	private $_dirty	= true;
+
+	/**
+	 * Hash
+	 *
+	 * @var string
+	 */
+	private $_hash	= null;
+
 	/**
 	 * Create a new worksheet
 	 *
@@ -644,7 +658,7 @@ class PHPExcel_Worksheet implements PHPExcel_IComparable
 	{
 		// Is this a 'rename' or not?
 		if ($this->getTitle() == $pValue) {
-			return;
+			return $this;
 		}
 
 		// Syntax check
@@ -675,13 +689,12 @@ class PHPExcel_Worksheet implements PHPExcel_IComparable
 			}
 
 			$altTitle = $pValue . ' ' . $i;
-			$this->setTitle($altTitle);
-
-			return;
+			return $this->setTitle($altTitle);
 		}
 
 		// Set title
 		$this->_title = $pValue;
+		$this->_dirty = true;
 
 		// New title
 		$newTitle = $this->getTitle();
@@ -817,6 +830,8 @@ class PHPExcel_Worksheet implements PHPExcel_IComparable
 	public function setProtection(PHPExcel_Worksheet_Protection $pValue)
 	{
 		$this->_protection = $pValue;
+		$this->_dirty = true;
+
 		return $this;
 	}
 
@@ -1629,6 +1644,7 @@ class PHPExcel_Worksheet implements PHPExcel_IComparable
 
 		if (strpos($pRange,':') !== false) {
 			$this->_autoFilter = $pRange;
+			$this->_dirty = true;
 		} else {
 			throw new Exception('Autofilter must be set on a range of cells.');
 		}
@@ -2176,25 +2192,29 @@ class PHPExcel_Worksheet implements PHPExcel_IComparable
 	 */
 	public function garbageCollect() {
 		// Build a reference table from images
-		$imageCoordinates = array();
-		$iterator = $this->getDrawingCollection()->getIterator();
-		while ($iterator->valid()) {
-			$imageCoordinates[$iterator->current()->getCoordinates()] = true;
-
-			$iterator->next();
-		}
-
+//		$imageCoordinates = array();
+//		$iterator = $this->getDrawingCollection()->getIterator();
+//		while ($iterator->valid()) {
+//			$imageCoordinates[$iterator->current()->getCoordinates()] = true;
+//
+//			$iterator->next();
+//		}
+//
 		// Lookup highest column and highest row if cells are cleaned
 		$highestColumn = -1;
 		$highestRow	= 1;
 
 		// Find cells that can be cleaned
+		$col = $row = array();
 		foreach ($this->_cellCollection->getCellList() as $coord) {
-			list($col,$row) = sscanf($coord,'%[A-Z]%d');
-			// Determine highest column and row
-			$highestColumn = max($highestColumn,PHPExcel_Cell::columnIndexFromString($col));
-			$highestRow = max($highestRow,$row);
+			list($c,$r) = sscanf($coord,'%[A-Z]%d');
+			$row[$r] = $r;
+			$col[$c] = strlen($c).$c;
 		}
+		// Determine highest column and row
+		$highestRow = max($row);
+		$highestColumn = PHPExcel_Cell::columnIndexFromString(substr(max($col),1));
+
 
 		// Loop through column dimensions
 		foreach ($this->_columnDimensions as $dimension) {
@@ -2224,20 +2244,22 @@ class PHPExcel_Worksheet implements PHPExcel_IComparable
 	 * @return string	Hash code
 	 */
 	public function getHashCode() {
-		return md5(
-			  $this->_title
-			. $this->_autoFilter
-			. ($this->_protection->isProtectionEnabled() ? 't' : 'f')
-			//. $this->calculateWorksheetDimension()
-			. __CLASS__
-		);
+		if ($this->_dirty) {
+			$this->_hash = md5( $this->_title .
+								$this->_autoFilter .
+								($this->_protection->isProtectionEnabled() ? 't' : 'f') .
+								__CLASS__
+							  );
+			$this->_dirty = false;
+		}
+		return $this->_hash;
 	}
 
 	/**
 	 * Extract worksheet title from range.
 	 *
-	 * Example: extractSheetTitle('test!A1') ==> 'A1'
-	 * Example: extractSheetTitle('test!A1', true) ==> array('test', 'A1');
+	 * Example: extractSheetTitle("testSheet!A1") ==> 'A1'
+	 * Example: extractSheetTitle("'testSheet 1'!A1", true) ==> array('testSheet 1', 'A1');
 	 *
 	 * @param string $pRange	Range to extract title from
 	 * @param bool $returnRange	Return range? (see example)
@@ -2245,30 +2267,17 @@ class PHPExcel_Worksheet implements PHPExcel_IComparable
 	 */
 	public static function extractSheetTitle($pRange, $returnRange = false) {
 		// Sheet title included?
-		if (strpos($pRange, '!') === false) {
+		if (($sep = strpos($pRange, '!')) === false) {
 			return '';
 		}
 
-		// Position of separator exclamation mark
-		$sep = strrpos($pRange, '!');
-
-		// Extract sheet title
-		$reference[0] = substr($pRange, 0, $sep);
-		$reference[1] = substr($pRange, $sep + 1);
-
-		// Strip possible enclosing single quotes
-		if (strpos($reference[0], '\'') === 0) {
-			$reference[0] = substr($reference[0], 1);
-		}
-		if (strrpos($reference[0], '\'') === strlen($reference[0]) - 1) {
-			$reference[0] = substr($reference[0], 0, strlen($reference[0]) - 1);
-		}
-
 		if ($returnRange) {
-			return $reference;
-		} else {
-			return $reference[1];
+			return array( trim(substr($pRange, 0, $sep),"'"),
+						  substr($pRange, $sep + 1)
+						);
 		}
+
+		return substr($pRange, $sep + 1);
 	}
 
 	/**
diff --git a/Classes/PHPExcel/Writer/HTML.php b/Classes/PHPExcel/Writer/HTML.php
index cad3205..57f393c 100644
--- a/Classes/PHPExcel/Writer/HTML.php
+++ b/Classes/PHPExcel/Writer/HTML.php
@@ -309,18 +309,18 @@ class PHPExcel_Writer_HTML implements PHPExcel_Writer_IWriter {
 		}
 
 		// Construct HTML
-		$html = '<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">' . "\r\n";
-		$html .= '<!-- Generated by PHPExcel - http://www.phpexcel.net -->' . "\r\n";
-		$html .= '<html>' . "\r\n";
-		$html .= '  <head>' . "\r\n";
-		$html .= '	<meta http-equiv="Content-Type" content="text/html; charset=utf-8">' . "\r\n";
-		$html .= '	<title>' . htmlspecialchars($this->_phpExcel->getProperties()->getTitle()) . '</title>' . "\r\n";
+		$html = '<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">' . PHP_EOL;
+		$html .= '<!-- Generated by PHPExcel - http://www.phpexcel.net -->' . PHP_EOL;
+		$html .= '<html>' . PHP_EOL;
+		$html .= '  <head>' . PHP_EOL;
+		$html .= '	<meta http-equiv="Content-Type" content="text/html; charset=utf-8">' . PHP_EOL;
+		$html .= '	<title>' . htmlspecialchars($this->_phpExcel->getProperties()->getTitle()) . '</title>' . PHP_EOL;
 		if ($pIncludeStyles) {
 			$html .= $this->generateStyles(true);
 		}
-		$html .= '  </head>' . "\r\n";
-		$html .= '' . "\r\n";
-		$html .= '  <body>' . "\r\n";
+		$html .= '  </head>' . PHP_EOL;
+		$html .= '' . PHP_EOL;
+		$html .= '  <body>' . PHP_EOL;
 
 		// Return
 		return $html;
@@ -374,8 +374,7 @@ class PHPExcel_Writer_HTML implements PHPExcel_Writer_IWriter {
 			// calculate start of <tbody>, <thead>
 			$tbodyStart = $rowMin;
 			$tbodyEnd   = $rowMax;
-			$theadStart = 0; // default: no <thead>
-			$theadEnd   = 0; // default: no </thead>
+			$theadStart = $theadEnd   = 0; // default: no <thead>	no </thead>
 			if ($sheet->getPageSetup()->isRowsToRepeatAtTopSet()) {
 				$rowsToRepeatAtTop = $sheet->getPageSetup()->getRowsToRepeatAtTop();
 
@@ -388,44 +387,43 @@ class PHPExcel_Writer_HTML implements PHPExcel_Writer_IWriter {
 			}
 
 			// Loop through cells
-			$rowData = null;
-			for ($row = $rowMin; $row <= $rowMax; ++$row) {
-				// Start a new row
-				$rowData = array();
-
-				// Loop through columns
-				for ($column = $dimension[0][0]; $column <= $dimension[1][0]; ++$column) {
-					// Cell exists?
-					if ($sheet->cellExistsByColumnAndRow($column, $row)) {
-						$rowData[$column] = $cell = $sheet->getCellByColumnAndRow($column, $row);
-					} else {
-						$rowData[$column] = '';
-					}
-				}
-
+			$row = $rowMin-1;
+			while($row++ < $rowMax) {
 				// <thead> ?
 				if ($row == $theadStart) {
-					$html .= '		<thead>' . "\r\n";
+					$html .= '		<thead>' . PHP_EOL;
 				}
 
 				// <tbody> ?
 				if ($row == $tbodyStart) {
-					$html .= '		<tbody>' . "\r\n";
+					$html .= '		<tbody>' . PHP_EOL;
 				}
 
 				// Write row if there are HTML table cells in it
 				if ( !isset($this->_isSpannedRow[$sheet->getParent()->getIndex($sheet)][$row]) ) {
+					// Start a new rowData
+					$rowData = array();
+					// Loop through columns
+					$column = $dimension[0][0] - 1;
+					while($column++ < $dimension[1][0]) {
+						// Cell exists?
+						if ($sheet->cellExistsByColumnAndRow($column, $row)) {
+							$rowData[$column] = $sheet->getCellByColumnAndRow($column, $row);
+						} else {
+							$rowData[$column] = '';
+						}
+					}
 					$html .= $this->_generateRow($sheet, $rowData, $row - 1);
 				}
 
 				// </thead> ?
 				if ($row == $theadEnd) {
-					$html .= '		</thead>' . "\r\n";
+					$html .= '		</thead>' . PHP_EOL;
 				}
 
 				// </tbody> ?
 				if ($row == $tbodyEnd) {
-					$html .= '		</tbody>' . "\r\n";
+					$html .= '		</tbody>' . PHP_EOL;
 				}
 			}
 
@@ -433,8 +431,7 @@ class PHPExcel_Writer_HTML implements PHPExcel_Writer_IWriter {
 			$html .= $this->_generateTableFooter();
 
 			// Writing PDF?
-			if ($this->_isPdf)
-			{
+			if ($this->_isPdf) {
 				if (is_null($this->_sheetIndex) && $sheetId + 1 < $this->_phpExcel->getSheetCount()) {
 					$html .= '<tcpdf method="AddPage" />';
 				}
@@ -477,14 +474,14 @@ class PHPExcel_Writer_HTML implements PHPExcel_Writer_IWriter {
 			// Loop all sheets
 			$sheetId = 0;
 
-			$html .= '<ul class="navigation">' . "\r\n";
+			$html .= '<ul class="navigation">' . PHP_EOL;
 
 			foreach ($sheets as $sheet) {
-				$html .= '  <li class="sheet' . $sheetId . '"><a href="#sheet' . $sheetId . '">' . $sheet->getTitle() . '</a></li>' . "\r\n";
+				$html .= '  <li class="sheet' . $sheetId . '"><a href="#sheet' . $sheetId . '">' . $sheet->getTitle() . '</a></li>' . PHP_EOL;
 				++$sheetId;
 			}
 
-			$html .= '</ul>' . "\r\n";
+			$html .= '</ul>' . PHP_EOL;
 		}
 
 		return $html;
@@ -524,8 +521,8 @@ class PHPExcel_Writer_HTML implements PHPExcel_Writer_IWriter {
 					// Convert UTF8 data to PCDATA
 					$filename = htmlspecialchars($filename);
 
-					$html .= "\r\n";
-					$html .= '		<img style="position: relative; left: ' . $drawing->getOffsetX() . 'px; top: ' . $drawing->getOffsetY() . 'px; width: ' . $drawing->getWidth() . 'px; height: ' . $drawing->getHeight() . 'px;" src="' . $filename . '" border="0" width="' . $drawing->getWidth() . '" height="' . $drawing->getHeight() . '" />' . "\r\n";
+					$html .= PHP_EOL;
+					$html .= '		<img style="position: relative; left: ' . $drawing->getOffsetX() . 'px; top: ' . $drawing->getOffsetY() . 'px; width: ' . $drawing->getWidth() . 'px; height: ' . $drawing->getHeight() . 'px;" src="' . $filename . '" border="0" width="' . $drawing->getWidth() . '" height="' . $drawing->getHeight() . '" />' . PHP_EOL;
 				}
 			}
 		}
@@ -555,20 +552,20 @@ class PHPExcel_Writer_HTML implements PHPExcel_Writer_IWriter {
 
 		// Start styles
 		if ($generateSurroundingHTML) {
-			$html .= '	<style type="text/css">' . "\r\n";
-			$html .= '	  html { ' . $this->_assembleCSS($css['html']) . ' }' . "\r\n";
+			$html .= '	<style type="text/css">' . PHP_EOL;
+			$html .= '	  html { ' . $this->_assembleCSS($css['html']) . ' }' . PHP_EOL;
 		}
 
 		// Write all other styles
 		foreach ($css as $styleName => $styleDefinition) {
 			if ($styleName != 'html') {
-				$html .= '	  ' . $styleName . ' { ' . $this->_assembleCSS($styleDefinition) . ' }' . "\r\n";
+				$html .= '	  ' . $styleName . ' { ' . $this->_assembleCSS($styleDefinition) . ' }' . PHP_EOL;
 			}
 		}
 
 		// End styles
 		if ($generateSurroundingHTML) {
-			$html .= '	</style>' . "\r\n";
+			$html .= '	</style>' . PHP_EOL;
 		}
 
 		// Return
@@ -659,7 +656,8 @@ class PHPExcel_Writer_HTML implements PHPExcel_Writer_IWriter {
 
 			// col elements, initialize
 			$highestColumnIndex = PHPExcel_Cell::columnIndexFromString($sheet->getHighestColumn()) - 1;
-			for ($column = 0; $column <= $highestColumnIndex; ++$column) {
+			$column = -1;
+			while($column++ < $highestColumnIndex) {
 				$this->_columnWidths[$sheetIndex][$column] = 42; // approximation
 				$css['table.sheet' . $sheetIndex . ' col.col' . $column]['width'] = '42pt';
 			}
@@ -862,8 +860,8 @@ class PHPExcel_Writer_HTML implements PHPExcel_Writer_IWriter {
 	public function generateHTMLFooter() {
 		// Construct HTML
 		$html = '';
-		$html .= '  </body>' . "\r\n";
-		$html .= '</html>' . "\r\n";
+		$html .= '  </body>' . PHP_EOL;
+		$html .= '</html>' . PHP_EOL;
 
 		// Return
 		return $html;
@@ -884,27 +882,28 @@ class PHPExcel_Writer_HTML implements PHPExcel_Writer_IWriter {
 
 		if (!$this->_useInlineCss) {
 			$gridlines = $pSheet->getShowGridLines() ? ' gridlines' : '';
-			$html .= '	<table border="0" cellpadding="0" cellspacing="0" id="sheet' . $sheetIndex . '" class="sheet' . $sheetIndex . $gridlines . '">' . "\r\n";
+			$html .= '	<table border="0" cellpadding="0" cellspacing="0" id="sheet' . $sheetIndex . '" class="sheet' . $sheetIndex . $gridlines . '">' . PHP_EOL;
 		} else {
 			$style = isset($this->_cssStyles['table']) ?
 				$this->_assembleCSS($this->_cssStyles['table']) : '';
 
 			if ($this->_isPdf && $pSheet->getShowGridLines()) {
-				$html .= '	<table border="1" cellpadding="0" id="sheet' . $sheetIndex . '" cellspacing="0" style="' . $style . '">' . "\r\n";
+				$html .= '	<table border="1" cellpadding="0" id="sheet' . $sheetIndex . '" cellspacing="0" style="' . $style . '">' . PHP_EOL;
 			} else {
-				$html .= '	<table border="0" cellpadding="0" id="sheet' . $sheetIndex . '" cellspacing="0" style="' . $style . '">' . "\r\n";
+				$html .= '	<table border="0" cellpadding="0" id="sheet' . $sheetIndex . '" cellspacing="0" style="' . $style . '">' . PHP_EOL;
 			}
 		}
 
 		// Write <col> elements
 		$highestColumnIndex = PHPExcel_Cell::columnIndexFromString($pSheet->getHighestColumn()) - 1;
-		for ($i = 0; $i <= $highestColumnIndex; ++$i) {
+		$i = -1;
+		while($i++ < $highestColumnIndex) {
 			if (!$this->_useInlineCss) {
-				$html .= '		<col class="col' . $i . '">' . "\r\n";
+				$html .= '		<col class="col' . $i . '">' . PHP_EOL;
 			} else {
 				$style = isset($this->_cssStyles['table.sheet' . $sheetIndex . ' col.col' . $i]) ?
 					$this->_assembleCSS($this->_cssStyles['table.sheet' . $sheetIndex . ' col.col' . $i]) : '';
-				$html .= '		<col style="' . $style . '">' . "\r\n";
+				$html .= '		<col style="' . $style . '">' . PHP_EOL;
 			}
 		}
 
@@ -920,7 +919,7 @@ class PHPExcel_Writer_HTML implements PHPExcel_Writer_IWriter {
 	private function _generateTableFooter() {
 		// Construct HTML
 		$html = '';
-		$html .= '	</table>' . "\r\n";
+		$html .= '	</table>' . PHP_EOL;
 
 		// Return
 		return $html;
@@ -962,12 +961,12 @@ class PHPExcel_Writer_HTML implements PHPExcel_Writer_IWriter {
 
 			// Write row start
 			if (!$this->_useInlineCss) {
-				$html .= '		  <tr class="row' . $pRow . '">' . "\r\n";
+				$html .= '		  <tr class="row' . $pRow . '">' . PHP_EOL;
 			} else {
 				$style = isset($this->_cssStyles['table.sheet' . $sheetIndex . ' tr.row' . $pRow])
 					? $this->_assembleCSS($this->_cssStyles['table.sheet' . $sheetIndex . ' tr.row' . $pRow]) : '';
 
-				$html .= '		  <tr style="' . $style . '">' . "\r\n";
+				$html .= '		  <tr style="' . $style . '">' . PHP_EOL;
 			}
 
 			// Write cells
@@ -1096,7 +1095,9 @@ class PHPExcel_Writer_HTML implements PHPExcel_Writer_IWriter {
 							// We must explicitly write the width of the <td> element because TCPDF
 							// does not recognize e.g. <col style="width:42pt">
 							$width = 0;
-							for ($i = $colNum; $i < $colNum + $colSpan; ++$i) {
+							$i = $colNum - 1;
+							$e = $colNum + $colSpan - 1;
+							while($i++ < $e) {
 								if (isset($this->_columnWidths[$sheetIndex][$i])) {
 									$width += $this->_columnWidths[$sheetIndex][$i];
 								}
@@ -1128,7 +1129,7 @@ class PHPExcel_Writer_HTML implements PHPExcel_Writer_IWriter {
 					$html .= $cellData;
 
 					// Column end
-					$html .= '</td>' . "\r\n";
+					$html .= '</td>' . PHP_EOL;
 				}
 
 				// Next column
@@ -1136,7 +1137,7 @@ class PHPExcel_Writer_HTML implements PHPExcel_Writer_IWriter {
 			}
 
 			// Write row end
-			$html .= '		  </tr>' . "\r\n";
+			$html .= '		  </tr>' . PHP_EOL;
 
 			// Return
 			return $html;
@@ -1282,11 +1283,13 @@ class PHPExcel_Writer_HTML implements PHPExcel_Writer_IWriter {
 				$lc = PHPExcel_Cell::columnIndexFromString($lc) - 1;
 
 				// loop through the individual cells in the individual merge
-				for ($r = $fr; $r <= $lr; ++$r) {
+				$r = $fr - 1;
+				while($r++ < $lr) {
 					// also, flag this row as a HTML row that is candidate to be omitted
 					$candidateSpannedRow[$r] = $r;
 
-					for ($c = $fc; $c <= $lc; ++$c) {
+					$c = $fc - 1;
+					while($c++ < $lc) {
 						if ( !($c == $fc && $r == $fr) ) {
 							// not the upper-left cell (should not be written in HTML)
 							$this->_isSpannedCell[$sheetIndex][$r][$c] = array(
@@ -1320,11 +1323,12 @@ class PHPExcel_Writer_HTML implements PHPExcel_Writer_IWriter {
 			if ( isset($this->_isSpannedRow[$sheetIndex]) ) {
 				foreach ($this->_isSpannedRow[$sheetIndex] as $rowIndex) {
 					$adjustedBaseCells = array();
-					for ($c = 0; $c < $countColumns; ++$c) {
+					$c = -1;
+					$e = $countColumns - 1;
+					while($c++ < $e) {
 						$baseCell = $this->_isSpannedCell[$sheetIndex][$rowIndex][$c]['baseCell'];
 
 						if ( !in_array($baseCell, $adjustedBaseCells) ) {
-
 							// subtract rowspan by 1
 							--$this->_isBaseCell[$sheetIndex][ $baseCell[0] ][ $baseCell[1] ]['rowspan'];
 							$adjustedBaseCells[] = $baseCell;