compute_train_stats: Fix logits passed in as proba (HumanCompatibleAI…

…#273)

Led to an error when I was training.

imitation: Bump version to 0.2.0

Final TF1 release

Clean up for PyPI Upload (HumanCompatibleAI#187)

* Update setup.py to prepare for PyPI release

* Remove stray __init__ file (was breaking pytype amongst other problems)

* Seals not benchmark_environments

* Rename benchmark_environments to seals

* Fix SEALS version

* Update configuration guidelines (now horribly out of date)

* Clarify contribution guidelines in README and update code coverage to have stricter check for project/main

* Add PyPi badge in anticipation of our glourious indexed future

* Update Ray to 0.8.x and make dependency optional