EXP-1280 FIX -- Minimized floaters associated with toolbar buttons should...

EXP-1280 FIX -- Minimized floaters associated with toolbar buttons should change the state of their parent button

* Toolbar buttons now display green when its corresponding floater is open or
  minimized.
* Made changes to buttons so flash time and rate is configurable
* Removed unused "highlight_color" attribute from LLButton
* Implemented "isVisible" function for toolbar button floaters.  It returns true
  when the floater is visible or minimized.
* Toolbar floater unminimize now also puts focus to the floater
* All commands now specify their "is_running_function" for toolbar button state
* ButtonFlashCount and ButtonFlashRate have been moved to button.xml settings
  and are now configurable on the button.  Toolbar buttons are set to never
  flash and this functionality is used to show which buttons have windows open.
* All toybox buttons show hover glow even when disabled

Reviewed by Richard.