Added enums for sub-branches of STL and Clones, and moved Class getter to being public

(cherry picked from commit bafd944e918a05824d6afc7344fdc70cfc153103)

Conflicts:
	tree/tree/inc/TBranchElement.h
	tree/treeplayer/src/TTreeReaderArray.cxx
	tree/treeplayer/test/hardTreeReaderTest.cpp