- Replace our custom path library with Fpath. It's rather more sturdy
   than our implementation after all.
 - Port over our old documentation extraction system to the new
   processor. This rather needs a rewrite, but all my attempts have
   ended in failure.

Also create the target directory if required.

This is a really dirty hack to make `_ENV.foo = 123` work the same as
doing `foo = 123`. This is largely useful for CC:T, where APIs do sneaky
things like this.

This allows you to declare "stub" files which define any additional externals.

 - Functions now store if they have an implicit self.
 - When converting a function to a method, check if we have an implicit
   self, or have an explicit self argument (dropping it if so).

 - Remove terms annotated with @Local in a post-processing step
 - Fix the parser recognising strings starting with `---`.

Also:

 - Rename "APIs" and "Libraries" to the more general "Globals" and
   "Modules". While there's no pretending illuaminate is designed for
   CC:T, let's not get too suck in its nomenclature.