Internals rewrite

[frostu8]

Currently, the gomori modloader is difficult to make commits to because of tangled code. Although this isn't really in demand, I've been working on a internals rewrite that applies some more principals like proper encapsulation and single-responsibility. The public API exposed will be the same, but all of the internal code has been rewritten and documented.

This is a big change, and I'm not sure if this is even the right way to go about it (considering modding is all about working with tangled code). Current PRs will have to be heavily rebased or even rewritten to match the new code.

See the code:
https://github.com/frostu8/gomori/tree/internal-rewrite