Unending Update: Sweeper v34.0

This update adds the Sweeper dungeon: A minesweeper inspired crawl where you must carefully reveal your surroundings.

After seeing Let's Revolution on the Thinky Games stream I was inspired by its use of minesweeper mechanics - hinting about potential threats under a fog war. Although I tried numbers to warn the player, it didn't quite fit. However, I found simple markers were enough. Especially when a wall-walker or a reanimator would step forwards out of the dark and complicate things.

I have also fixed a bug where the E nodes would not unlock levels beyond them until you restarted the game.