New testing for features of "dragndrop_file_upload".

WARNING: broken backward compatibility (moved some exceptions to "Uploader" class from "DragNDropFileUpload").
refactoring (anonymous functions) for "dragndrop_file_upload"
"dragndrop_file_upload": replaced deprecated ArrayBuffer to other way
gulp for "dragndrop_file_upload" (separated to modules, r5)
"dragndrop_file_upload": "distclean" task for gulp
"dragndrop_file_upload": added unit-tests by build with debug: true in package.json (r6)