[PATCH] [C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges.

[David Blaikie]

LGTM

(In follow up many of these could be std::one_of, std::any_of, none_of, etc - though we could add llvm versions of those that work on ranges directly (rather than iterator begin/end))

http://reviews.llvm.org/D4481