Created chat common javascript module/css/template file
Put ChatButton in livechat
Some cleaning
Ported most of the old im.js to im_common.js
Fixed a lot of stuff to make it work again in live support
Removed to_url
Solved bottom offset problem
Solved style problems identified by jshint
[IMP] im, im_livechat: big refactoring to unite the JavaScript used by those two modules under a common JavaScript module