Publish on PyPI

[simonschmidt]

It'd be nice if this package was available on PyPI to make installation easier

I was experimenting a bit with poetry and I would suggest something like:

• Create a fygen directory and move fygen.py/fygen_help.py/wavedef.py code in there
• Export relevant public interfaces from __init__
• Update documentation accordingly
• Maybe move some constants/exceptions to their own files
• Get rid of sys.path modifications in the examples

If you're interested in this I can provide a PR for it while also dropping python2 support.
What would remain to do is to actually publish to PyPI.

It might also be worth looking into setting up CI to automate releases from github - but I think that's less important and something that could be done later if desired.

[mattwach]

I think this is a great idea overall.

I have mixed feelings about dropping python2 support as it may make the library difficult for some people to use. Maybe the six library can be used to support both python 2 and 3?