Board.next_player
Game.next_player()
First bit of Board.legal_moves

Makes sure the correct pass move is always included
Make coord tests a submodule of coord
Coord::for_board_size
Finished implementation of Board.legal_moves
Game.legal_moves
Use Board.legal_moves in RandomEngine
Reformat GoGui commands
Merge pull request #44 from ujh/legal-moves

Add legal_moves method to Board

Fixes #42