GitLab

I need there to be separate packages for:

- the typed.Node interface, and any top level helpers;
- the typesystem implementation
- the typesystem *declarations* (distinct because it's what you
 construct when parsing the ast -- doens't contain pointers yet)
- and (eventually) a parser and a fmt package for the ts declarations.

And right now all those are heaped together.

Not sure where the validate method -- the thing that's actually touched
in this diff -- will end up.  Either the top level, or the typesystem
implementation package, probably.
Signed-off-by: Eric Myhre <hash@exultant.us>