DONE 1. Add type:guid

DONE 1. Add type:guid
2. Allow guids in queries
3. Extract guids correctly from query results
4. Implement cache/context object
5. Cache structs in find -- g:find should add structurs to the cache
6. save and delete should update the cache
7. optimise find-by-guid to go by the cache first
8. create find-by-guids : (listof guids) -> (listof struct) which goes via the cache
9. add relationships in model
10. generate accessors that understand and lazy load relationships.  e.g. student-advisor accessors from student-advisor-id accessor