FanBoxes: fixed to be compatible w/ MW 1.21.

Swapped sajax_* functions to jQuery and removed FanBox_AjaxFunctions.php
in favor of the new API module (refs bug #53119).

Lots of general fixes all over the place.

Bumped version number to 3.0.

Change-Id: Ida6c67be791eaff64b05d3352be8aeec00582b84