Update GroupRolePicker to be RockControl
- fixed up "circular file references are not allowed" which seemed to be caused by the fullpath references to MasterPages in the Layout aspx files.  Now they no longer use the full path (which isn't needed since the .master file is in the same directory).  This should also make creating new themes a tiny bit easier since the master page references dont need to be edited to reference the new path.
Merge branch 'develop'