Add more abstraction to games

[Pirvu2k]

At the moment there is a lot of duplicate code for games, we should find a way to facilitate polymorphism and reuse common functionality more easily. The idea here would be to either use an OOP-style approach with classes and inheritance or some sort of map like we use for commands.

For example, skribbl.py uses a lot of code from speed_dating.py , and any more games that we add in the future should have this common functionality extracted elsewhere.