The async-confirm branch doesn't work well with the jQuery Form plugin

[xhh]

After switching to the async-confirm version of jquery-ujs, my code which uses jQuery Form plugin's ajaxForm and ajaxSubmit no longer works as before:

1. the beforeSubmit validation function doesn't get called any more,
2. the form does a normal submission while an ajax-submission is expected.

(The jQuery Form plugin: http://jquery.malsup.com/form/)

I guess there is something wrong with form submission handling in that branch, which breaks the normal submission process.