Respect unsigned fields when tables get converted to entities.

This is working on our mysql setup, however i have no idea of the consequences of this change when using other RDBMSes.

lib/Doctrine/ORM/Tools/EntityGenerator.php

@@ -1431,6 +1431,10 @@ public function __construct()
                 $column[] = 'nullable=' .  var_export($fieldMapping['nullable'], true);
             }
             
+            if (isset($fieldMapping['unsigned']) && $fieldMapping['unsigned']) {
+                $column[] = 'options={"unsigned"=true}';
+            }
+            
             if (isset($fieldMapping['columnDefinition'])) {
                 $column[] = 'columnDefinition="' . $fieldMapping['columnDefinition'] . '"';
             }