NPC-308 Remove external python dependencies

*NOTE* this is not ready to merge.  Having trouble building locally in OS X environment, but it does work in the Travis Linux environment in both 2.6 and 2.7, with one caveat: It's explicitly re-building the nupic-linux64 environment every time, as I've yet to commit and push the updated changes to nupic-linux64.

On OS X, I'm having the same problems with ft2font.so as encountered in https://github.com/numenta/nupic/pull/141