Stability [Alpha 20]

This update has a subtle change to the UI that required a lot of work under the hood.

One noticeable benefit of this is being able to see a preview of what a theme looks like under Settings.

Some graphics issues were also fixed.

Next on my list is creating some dungeon code that will essentially treat a series of puzzles as dungeon rooms. This allows me to drop a newbie into a tutorial level when they open the game for the first time. It could also form the basis of other dungeons as well.