SWFUpload Code

- Added upload_limit parameter. This allows an error to be returned after X files are uploaded.
- Fixed bug where an error in one upload stopped all other uploads. Also manifested as preventing new uploads from being processed.

mmSWFUpload: Added setting for upload_limit
MultiUploadDemo/Default.aspx: Added init parameter for upload_limit
MultiUploadDemo/Default.aspx.Handlers.js: Added error handler for -60 (upload limit reached)
FormsDemo/Default.aspx.Handlers.js: Added error handler for -60 (upload limit reached)