Merging.  There's a bug right now, and I'm trying to find out where and why that is.

Signed-off-by: Daniel Shumway <shumway.danny@gmail.com>
Adding and subtracting working as intended.  Reverted two lines in level to a previous version to fix bug that was causing snake to spawn infinite tiles in rows of 3 to the right during movement (left old code in commented out).

Signed-off-by: Daniel Shumway <shumway.danny@gmail.com>