Puzzle Polish

This update has 30 puzzles to try and an overhaul of the user interface.

Hopefully the game looks a bit more polished. Puzzle mode has an updated level selector and preview, the rolling food clock is back, gamepad detection is supported, and the title screen looks a bit snazzier. We're getting close to the point where I'll be working on a paid version with many more levels and achievements to hunt for in the unending mode.

I may even include levels from the original Ending. This is something of a stretch goal requiring a branch of the engine that can behave the way the old one did. But being able to play those levels with undo would be worth it.

Apologies for this version being extra large but text seems to failing to render at lower resolutions. This might be a bug in the version of Unity I'm using.