First version of directdb approach that actually runs.  It seemed to put
instance and holdings data in, but didn't cascade the persisting of
items, extent of ownership, etc.  Probably because I took all the
cascades out during my confusion over how to fix the "detached object"
exception.  I'll put them back in.

I also added some maven dependencies, adapted persistence.xml, and
created a new embeddable "FlatLocation" class.  The old location class
had nested, embeddable locationlevel instances in it that led to
infinite embedding ...