Post 7DRL work

I decided to continue working in the game and make it even more fun and interesting :) The original 7DRL version will be kept for reference and for the jurors to evaluate, of course.

After some much-needed post-7DRL Challenge refactor, I'm tackling a big one to get it out of the way early: Saving and Loading games. As usual, using my own `circular-functions` lib, which continues to work great after all these years. Of course, having to do some pretty big changes under the hood to optimize the data. Right now it's about 20MB of serialized data at startup.

This one's big enough to warrant it's own new release, so I'll keep you informed!