Formalise documentation

[nelsonxb]

The stuff in green.h right now is kind of okay... for me, being that I wrote it and already know what's going on. Could probably use a fair bit more detailed documentation for literally anyone else.

[nelsonxb]

This is basically done as of 7e813e2. I'm gonna leave this open until hosted web docs are a thing, but for the most part the documentation is done (for now).