Refs #1845, added new admin page where users can create their own custom JavaScript tracking code snippets and image tracking link HTML.

Notes:
  * Rewrote Site selector widget JS so multiple site selectors could be used on the same page.
  * Added method to ajaxHelper JS class that eases use of bulk request API.
  * Allowed section toggler JS in misc.js to be used w/ input elements as well as links.
  * Fixed bug in menu ordering code where accessing _hasSubMenu results in uasort behaving incorrectly when menu is already sorted.