[#32033] Removing MooTools dependencies from overrider.js

Under GSoC MooTools to jQuery project, this PR removes the MooTools dependencies in media/overrider/js/overrider.js file.

Feature Tracker Item:
http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=32033&start=550