From valeriy Ounchin:

-  protection added in several methods of TGWin32 class
-  add asignment of gInterpreter, gVirtualX to "real objects" in TGWin32::CloseDisplay()


git-svn-id: http://root.cern.ch/svn/root/trunk@8094 27541ba8-7e3a-0410-8455-c3a389f83636