Prevent unwanted progress event on chunked uploads. Closes #2082.
Make sure the preview rendering resolves. Fixes #2069.
Update to jQuery 1.9.1.

This allows to remove the workaround introduced here:
https://github.com/blueimp/jQuery-File-Upload/commit/d64d95a329850415258
767b3eb5c55f147e31aee
Upgraded jQuery UI widget factory (only version change).
Updated download and support information.
Skip transitions for invisible nodes. Fixes #2105.

This is not only more efficient, but also required since it seems
transition events are not fired for invisible elements.
Simplify click event handler selectors. Closes #2122.