A Rust implementation of the Lox bytecode VM from Crafting Interpreters

This passes the test suite from the book repo! But wouldn't be surprised if I introduced some bugs somehow 😅

Almost every interesting line in this interpreter is wrapped in unsafe because it's a function-by-function port from my clox code.

I tried to make some things safer, but I don't (yet?) have the knowledge/skills I need to safe-ify the whole thing. Although maybe it makes sense that the garbage collector has no shoes can't be made safe?