Resolves: #i123841# fix constness issues in OSX 64bit clipboard handling

(cherry picked from commit 0801e9b488660e792a09d12717da951d224b26e0)

Conflicts:
	vcl/aqua/source/dtrans/DataFlavorMapping.cxx
	vcl/aqua/source/dtrans/DataFlavorMapping.hxx
	vcl/aqua/source/dtrans/aqua_clipboard.cxx
	vcl/aqua/source/dtrans/aqua_clipboard.hxx

Change-Id: Ifaf90c9aafcc22dd93923250d2342346806f9e88