This avoid the ugly hack of keeping a referenec in GameState

Intention is the game hands control to AI player after human ends turn by
calling this method

TurnDemo class not really necessary but illustrative

There is a display bug on the frontend with this- it isn't quite aligned with
Player 2's RHS avatar

Can use this on AI turns etc to send messages back to frontend

Generated using
https://www.toptal.com/developers/gitignore/api/sbt,playframework

and also ignored the game sprites / other UI images