Fixed reference to the _getXHRPromise method.
Expose the number of active uploads as .fileupload('active') widget method.
Provide a .response() method on the data argument to retrieve response data.
Make sure the progress and response container objects are initialized.
Ensure the same state for the done, fail and always events.
Prevent errors when passing a non-object type as formData option.
Use the faster (new Date()).getTime().

See http://jsperf.com/date-now-vs-new-date-gettime/4
Merge branch 'master' of git://github.com/blueimp/jQuery-File-Upload