thus constant (by nature) function modifies object's state. This makes it impossible
   to paint the same widget twice by calling DoRedraw, the second time exposed region is empty.
   This does not work with cocoa.
2. CreateFontCollection for a specific name always finds only 1 font, not all variations of the same font,
   instead I have to request the full list every time and filter it myself.
3. TGFontDialog: connects signal/slot only for gVirtualX inherited from TGX11 (or TGX11 itself),
   must also work for TGCocoa. all_sizes and all_styles variables also were set incorrectly for TGCocoa
   (initialization uses check InheritsFrom("TGX11")).


git-svn-id: http://root.cern.ch/svn/root/trunk@44185 27541ba8-7e3a-0410-8455-c3a389f83636