Code cleanup and migration to Python 3

[Hydraze]

Hello, This PR contains massive code cleanup (code is now nearly PEP8 compliant) and modifications to make it work with Python 3. I tested many features but I may have missed something.

[cornfeedhobo]

it's too bad this got so out of date :-(

[whoot]

Indeed, would love to see an update where policy masks are statistically arranged.

[Hydraze]

@cornfeedhobo @whoot out of curiosity, what features are missing exactly/what should be updated?

[RaphaelJoannou]

hydraze thank you so much for this, you're a bloody legend