cms cxx11 custom attribute handling for clang 3.4

Conflicts:
	lib/Parse/ParseDeclCXX.cpp
	lib/Sema/SemaDeclAttr.cpp
make thread_guard and thread_safe work with var and function decls
cms::thread_guard parsing working correctly finally

Conflicts:
	lib/Parse/ParseDeclCXX.cpp
Don't warn on FieldDecl's