Cleaning & fixes:
* Added comments/documentation.
* Some better errors.
* Generated names for structs should be better?
* Efficiency adjustments.
* Discrete sets in typechecks now allow commas in quoted strings.
* Virtual keys are now secondary.
* imports from RPL struct will handle UTF8 properly now.
* Prevent recursive inclusion.
* Path.string() works properly now.
* Added missing lvalue/rvalue exceptions for math.
* Added Math.__unicode__