Tests: reset drag DataTransfer on external drop.
Tests: getData Firefox fix.
Rename fileLoader to FileLoader. Tests: FileLoader constructor.
Tests: added FileReaderMock and XMLHttpRequestMock.
Tests: added loaders events observer.
Fixed total file size bug. Tests: improved file reader mock and events observer.
Fixed uploaded size bug. Tests: upload test.
Tests: added URL to all events observer.
Tests: Added uploadUrl assertion.
Tests: loadAndUpload, real file for tests.
Fire abort event when loader is aborted just after creation. Tests: Abort tests.