Maya2015

This gets us a building and running plugin against the niftools fork.
Solution design stripped down to be able to practically maintain many different Mayas.
Tested with 2015-x64, 2013-win32, 2013-x64, by importing, editing and exporting Skyrim childhead.
I have no idea what the full feature set is, but UVs were preserved so yay.

Git-flow would dictate that you pull this into niftools:maya2015 and not niftools:master, yes?

Can you open issues for this, if it is generally broken through NifLIb updates.