Fixes a XSS issue in ExternalCalls.

Bug: http://code.google.com/p/swfupload/issues/detail?id=376

Author: sir-gawain

core/Flash/SWFUpload.as

@@ -232,6 +232,7 @@ package {
 
 			// Get the movie name
 			this.movieName = root.loaderInfo.parameters.movieName;
+			this.movieName = this.movieName.replace(/[^a-zA-Z0-9\_\.\-]/g, "");
 
 			// **Configure the callbacks**
 			// The JavaScript tracks all the instances of SWFUpload on a page.  We can access the instance