added some tasks to binarycpython c sourcecode

 * TODO: Put in clear debug statements

 * TODO: properly return stderr

 * TODO: describe all functions with docstrings

 * TODO: properly pass through all the pointers using Capsules:  

    https://docs.python.org/3.6/c-api/capsule.html#c.PyCapsule_New

    https://gist.github.com/Sleepingwell/5259476

    https://bfroehle.com/2011/07/18/python-capsules/

    https://docs.python.domainunion.de/3.6/howto/cporting.html

    https://lappweb.in2p3.fr/~paubert/ASTERICS_HPC/5-6-3-651.html

    https://www.geeksforgeeks.org/c-api-from-extension-module-in-python-set-1/

    http://pageperso.lif.univ-mrs.fr/~francois.denis/IAAM1/python-3.6.5rc1-docs-html/howto/cporting.html

    http://python3porting.com/cextensions.html

 */