Add MIT license blocks to src/openseadragon.js

for code taken from jQuery and from mattsnider.com.

Ideally we'd keep the MIT-licensed helper code in a separate file,
but it proved difficult to extricate from the rest of openseadragon.js.

Also remove comment about plagiarism.  It's not plagiarism if it's
attributed and properly licensed.

src/openseadragon.js

@@ -31,6 +31,57 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+/*
+ * Portions of this source file taken from jQuery:
+ *
+ * Copyright 2011 John Resig
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/*
+ * Portions of this source file taken from mattsnider.com:
+ *
+ * Copyright (c) 2006-2013 Matt Snider
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT
+ * OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR
+ * THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+
+
  /**
   * @version  <%= pkg.name %> <%= pkg.version %>
   * 
@@ -331,9 +382,9 @@ window.OpenSeadragon = window.OpenSeadragon || function( options ){
  *  namespace.  Many, if not most, are taked directly from jQuery for use
  *  to simplify and reduce common programming patterns.  More static methods 
  *  from jQuery may eventually make their way into this though we are
- *  attempting to avoid substaintial plagarism or the more explicit dependency
+ *  attempting to avoid an explicit dependency on jQuery only because
- *  on jQuery only because OpenSeadragon is a broadly useful code base and
+ *  OpenSeadragon is a broadly useful code base and would be made less broad
- *  would be made less broad by requiring jQuery fully.
+ *  by requiring jQuery fully.
  *
  *  Some static methods have also been refactored from the original OpenSeadragon 
  *  project.