Add the preference pane
Define makeWholeGameTree
Toggle the preference pane between games
Expand margin-top of #preference-pane
Toggle enabled status, not visibility
Keep the last game board
Use #start-button as the UI to reset game
Use primitive values to drawGameBoard
Draw the initial game board at startup
Emphasize disabled status
Remove verbose makeWholeGameTree
Record the current player types
Choose move according to player type