Feature Request: Multiplayer mode

[JogoShugh]

Students want to play against/with their friends at the same time.

Some things about this:

• Enemies currently have a random motion, we'd need to generate their motion from the server, and broadcast the motion out to each connected user
• This means:
  • Option 1: Have a server-side stateful memory of the current game state. Not impossible.
  • Option 2: Make the "Host" generate the state and send it to the server and the server then forwards it along.
• We probably want to do this with socket.io, not meteor collections for performance reasons.