Fixes regression bug with document filter.

Document filter selects and checkboxes didn't do anything, now they do.

Regression introduced by https://www.pivotaltracker.com/story/show/52381589

I wasn't able to determine how it used to work before the bug was introduced.  The events weren't being bound anywhere and the script hadn't been changed for a while.  I can only guess that something else was causing changes in selects to submit the parent form.