[C++11] Add range views for various parts of a Module.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203394 91177308-0d34-0410-b5e6-96231b3b80d8
[LCG] Simplify a bunch of the LCG code with range for loops and auto.
Still more work to be done here to leverage C++11, but this clears out
the glaring issues.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203395 91177308-0d34-0410-b5e6-96231b3b80d8