IRI validation should be done via lib.. these don't really do much
- not checking raw is in range of min/max, if present
- iri not complete
- not validating lang codes
- group doesn't test member/ifi requirement
- group not done, yet
- group as the object not working
- group as the actor not working
- interaction activities aren't great
- attachment contentType just does a pattern match
- doesn't look for substatements in substatements