Fix coverage badge.
Refactor out node building logic.
Remove member variable.
Remove extra method.
Rename board to game state.
Build basic board construct.
Override copy method.
Add corner space method.
Add board dependency to game-state.
Refactor out and inject board class.
Switch board injection to setter.
Add to_a to board and some refactoring.
Refactor board methods.
Add simplified make_move method.
Switch to make_move.
Refactor away piece in player.
Clean up cruft and refactor methods.
Refactoring and profile tuning.
More performance tuning.
Add check for imposible lines for speed.