[RFC] cpp11-migrate tool

I recently posted a review request for a nullptr conversion tool and was reminded that from my previous solicitation for advice from this list that a single tool to do all C++11 transformations is preferred. So I've put together a design document for such a tool that I'd like feedback on. It's pretty straightforward but I wanted to be sure the initial features for the tool are sound and the way forward for future improvements makes sense.

https://docs.google.com/document/d/1xXfpLPxXIlp3pUpASXC547sQFF-vvHhnQkRBogM9wX0/edit

I think this looks great, btw. :slight_smile: