Allow moving pieces by clicking squares

From last week's user feedback, we found that the users found it difficult to move pieces using the current movement input process, which is isolated from the actual game board. This issue will migrate commands for moving pieces into simply clicking the board of the game.

1. Select piece to move
2. Indicators will appear showing what squares can be moved to
3. Click one of the marked squares to move the piece. Clicking any other square will deselect the originally selected piece