Added licenses to our project and updated the readme.

I realised we never actually formally released this under an open source license so I added one (in fact two since GPL doesn't cover images) and all the necessary paper work.
I also updated the readme to reflect it and make the project look a bit less 1990s.

Had to do it this way since I don't think I had my github when we set up so I'm not on the repo :'(.