Implement screen integration so you can play with any client as long as it can capture on the screen

[CmdrDats]

This should be a 'cheap' way to integrate with every go client, effectively. It needs:

1. A way to specify a rectangle on the screen where the board exists
2. Read the board state and create a new game.
3. A way to tell which moves should be submitted as mouse clicks (player colour + stable board state)