Fully separate the core code of miratope

[vihdzp]

Currently, Miratope consists of lots of complex polytope building code, and lots of complex polytope rendering code. We ought to separate these so that the crate is easier to use by others.

Before this separation is fully complete, there's a few things we need to sort out:

• Verify that the public and private parts of the API make sense.
• Feature-gate all parts of the code that might not be strictly helpful.
• Feature-gate the abstract name representations and the language module.
• Add thorough documentations.

[vihdzp]

Instead of feature-gating the abstract name representation, I just made it separate altogether. Made the code much cleaner.