Added resuming of game from localstorage

Hi, I've added support for persisting and reloading the game stage.  On each move, the GameManager and Board state are serialized to LocalStorage (just before the Actuator runs).  On load if the game state is present, the GameManager and Board are initialized based on the saved state, otherwise they initialize normally.  Since reloads do not reset the game anymore, I've added a New Game button above the board (the styling and placement, I'm not crazy about).

This, along with the cache manifest PR would make for a 100% offline app.