This adds the option to generate random terms that satisfy
judgment-forms and metafunctions.
Currently functionality does not include:
- patterns/terms using: ellipses, in-hole/hole and relatives, side-conditions, unquotes
- define-relation
- redex-check integration
redex patterns a bunch:
- repeats are turned into wrappers in sequences,
- names are all explicit,
- non-terminals are wrapped with `nt',
- cross patterns always have the hyphens in them.
- ellipses names are normalized (so there are no "hidden"
name equalities); this also means that repeat patterns
can have both a regular name and a mismatch name
Also, added a match-a-pattern helper macro that checks to make sure
that functions that process patterns don't miss any cases
