organize all of the files

[catdad]

Okay, no more "putting all the stuff in one folder". It was fine when there were 3 files, but there's a ton of them now.

• [ ] organize the lib folder... is this supposed to be called src?
• [ ] organize the test folder to match lib
• [ ] split apart large test files (I'll limit this to tests for now, the lib folder is a different effort)