Basic board transition

This moves some code from the currently unused `baseObjectMove` into the Player object's custom `update` call. I've modified it slightly since the `baseObjectMove` code requires an x/y coordinate of the current object, so we now grab that from the tile array for the board.

There is probably going to be a need for x/y coordinates on every single object, and it might make sense to set up a kind of (class-based?) inheritance system.

(Side note, I'm really excited to see this project here, and I hope you're taking pull requests! It would be great to turn this into an actively-developed thing.)