Caterpillar

The new focus is to implement interactive programming. But before I launch into that directly, I want to pave the way with a bit of cleanup first.

I was able to port the game to the browser so quickly, because of a heavy stack of dependencies that I was already using, and that happen to work in the browser too. This setup is quite bloated (manifesting in slow compile times). It's also designed for running Rust in the browser, not to support a whole new language.

All of that is probably fine for now, so I want to be opportunistic about this cleanup. Simplifying now saves time later, but it's not worth getting stuck on. Since I don't know how long this will take, nor how much time it can save, I don't have a strict limit. As long as there's progress and I'm happy, all is good. If I'm not done in a few weeks, I can re-evaluate.