Pydagmc Merge and Cythonization

This is not my best work, but it may be some of my fastest.  I blame most of this on the poor design of pydagmc which stores most of its state globally - and thus only allows one file to be open per process...I think.  I have tried to clean up much of the formatting issues.  

I left the API mostly intact and only changed some of the wrapper functions and only where it made sense.  This should help people migrate.  However, in the long term I think that this should be cleaner up.  Probably most of the functionality should live on Mesh.

All tests pass.  

Note I pulled in all of history of the original repo (https://github.com/svalinn/pydagmc).  Credit where credit is due :)

Closes #239