- further changes to attributes with regards to "trackparent". the "commit" operation

- further changes to attributes with regards to "trackparent".  the "commit" operation
now sets a "hasparent" flag for all attributes to all objects.  that way lazy loads
via callables get included in trackparent, and eager loads do as well because the mapper
calls commit() on all objects at load time.  this is a less shaky method than the "optimistic"
thing in the previous commit, but uses more memory and involves more overhead.
- some tweaks/cleanup to unit tests