Containerize project

[roclark]

To ease installation, setup, and usage, it is highly recommended to run gym-mupen64plus in a Docker container. That way, the code can easily be run anywhere that supports Docker instead of trying to replicate a supported environment. Most of the context here has been discussed in #68, but the core of this update is the following:

• Rebase the dockerize branch created by @bzier on top of master to get the latest changes (including support for Super Smash Bros.).
• Update the README to reflect the discovery that using render() inside of a container makes the screen appear frozen while running and should be avoided.
• Include ffmpeg as one of the installed packages in the Docker image to support recording runs using gym's Monitor wrapper.
• Directly copy the provided smash.sra file to mupen64plus' game save location using the expected filename to unlock everything in Super Smash Bros.

Closes #68

Signed-Off-By: Robert Clark robdclark@outlook.com

[roclark]

Thank you both for the reviews! Just made some updates based on your comments and re-pushed the changes. Also, happy to help get this branch done! It was already in great shape, just needed a few minor tweaks.

[kevinhughes27]

🎉