Add to PyPI

[jkiv]

Might as well make it easy to get/install python3 bindings, now that shapool-client is dependent on it.

[jkiv]

How to deal with architecture dependence of C code?

[jkiv]

Add platform specific wheel?

• https://stackoverflow.com/questions/51527148/pip-install-and-platform-specific-wheels
• https://www.python.org/dev/peps/pep-0425/#id1