These functions make possible porting the tools from the sculpt branch, making them compatible with PBVH_FACES and #PBVH_BMESH## without duplicating the code. They can also help to simplify some existing code.
I ported some operators in the sculpt branch and they are working fine with dyntopo enabled. I think those are the most problematic operators, but maybe I'll need to add more functions to this API in the future. This should be enough to start making the final patches for most of the tools.