Help popover for the "Released" column on the application deploy page

Addresses this ticket:
http://manage.dimagi.com/default.asp?115954#682855

I replicated the javascript used in the `corehq/apps/users/templates/users/mobile/users_list.html` template to create the pop-over. Clicking the heading shows the pop-over, and clicking the heading again hides it. This is the same functionality as the [aforementioned page](http://www.commcarehq.org/a/noahtest/settings/users/commcare/). I noticed that on [some pages](http://www.commcarehq.org/a/noahtest/settings/users/web/) the pop-over is hover activated though. Is there a preferred method?