Support one single PCM for ROOT to simplify PCM merging:
load single PCM during startup if it exists; then don't load any subsequent PCMs for ROOT.


git-svn-id: https://root.cern.ch/svn/root/trunk@48654 27541ba8-7e3a-0410-8455-c3a389f83636
Remove TGLFormat.h include from TGCocoa.


git-svn-id: https://root.cern.ch/svn/root/trunk@48655 27541ba8-7e3a-0410-8455-c3a389f83636