EXP-1205 PROGRESS -- As a User, I want a toybox which will contain all buttons...

EXP-1205 PROGRESS -- As a User, I want a toybox which will contain all buttons that I can d&d into the toolbars
EXP-1232 FIX -- Create class to load and hold all of the command meta data associated with FUI toolbar actions

* Added basic commands.xml file to define FUI-related toolbar actions.  For now
  a basic "avatar" and "places" button are defined.
* Added basic command manager to parse and hold strings that define potential
  toolbar command actions.
* Broke out a separate floater function as a placeholder for the 3-state toolbar
  floater toggling.
* LLUI::initClass now parses the new commands.xml file

Reviewed by Richard.