Replace `make` stuff to python stuff

Fixes #1618.

This PR was created to simplify #1579 . Its objective is remove `make` stuff as the repository will be fully pythonic. 

Detailed changes in logic order:
- Remotion of custom targes from CMakeLists.txt
- Readme updated with python instructions

CC: @oxtopus @rhyolight @scottpurdy 
@rhyolight @oxtopus @scottpurdy 

Look this:
https://github.com/numenta/nupic/pull/1622