Won field added to BoardNode

DecisionMaker marks the leaf if won
BoardNodes get a marker who wins the game. This should simplify the decision making process.

Tests created for the above. Passed.
Revert "BoardNodes get a marker who wins the game. This should simplify the decision making process."

This reverts commit a0d976a8ceb028d0faa17a3cf44e57d160c53d47.