Gym Super Mario Bros Versions Save

Update with new RandomStages environment that samples stages at random.

Fix links in README for PyPi

the older iterative implementation outperforms the current vectorized numpy implementation. Reverting for the better performance (and more understandable code).

update the version of nes-py

Implement the get_action_meanings method in the SuperMarioBrosRandomStagesEnv environment.

fix the RNG name to work with gym wrappers.

Initialize RNG in nes-py base environment for compatibility with wrappers.

Remove deprecated usage of deprecated wrap feature in nes-py

Update nes-py version that has a breaking change in it.

better consistency with naming schemes in the project and the game in general.