Interim commit for updating kernel contracts to suppport iterators

Partial resolution of: https://www.pivotaltracker.com/story/show/59243236

Distinguishing between managed and unmanaged RDF
Developing machinery to compare new and old material for updating
Building new iterator-driven persistence machinery
Continuing to build iterating persistance machinery
Completed positive persistence
Moved iterating RDF generation to the outer layer of JcrRdfTools
Moving iterated generation of versioning-related triples through to the domain models