A fix for: https://github.com/LPology/Simple-Ajax-Uploader/issues/50

Fixed the problem by adding the "appendFilenameToUrl" setting (true by default). Also, when the "data" object is empty "appendFilenameToUrl" is set to false , URL isn't modified at all. Now the uploader can be used for GAE apps under XHR-capable browsers (haven't yet tested it with older ones).