Setuptools, python3, Cython compliance

[eugeneai]

Hi!

This pull request if accepted should be a branch like "python3" as not tested well and will not work in python 2.x for sure.

1. setup.py now is based on setuptools. We can do python setup.py develop.
2. All modules now work in python3, and, hence,
3. bison_.pyx now Cython-compliant, language level 3.
4. I run calc, calc1 tests; they work well.
5. I've merged some code from csarn as he tried the same early.

Best regards, Evgeny
and thank for csarn.

[csarn]

Thanks, this is great! I wasn't sure my code was pull-request-worthy so far, but I didn't get around to further work on it.