Added the following for increased LLBadge functionality:
* Panels now choose whether or not they accept buttons as children, which they
do by default.
* UI controls now shuffle controls with "requests_front" to the front of their
children list at postBuild time.
* Badges are set to "requests_front" by default
* Badges now accept border image and color attributes
Reviewed by Callum
Leyla Farazha