v1.1.0 Now with Undo

Undo now replaces the reset button in the top right of the screen and also the "R" keyboard command. It's much easier most of the time to undo a few steps than reset the level, however you can still reset the level by opening up the menu and selecting "Restart Level".

I had built the command structure early in the prototype for undo, but never fully got it working. I did a quick test, and in a few lines of code I got it working, but with a few bugs. I cleaned up the logical and visual sequencing to deal with bugs related to undo, and actually a few existing edge case bugs too.