Updated fcr:versions to return more useful triples, fcr:content to work on old versions.
Merge pull request #167 from mikedurbin/versioning-2

Updated fcr:versions to return more useful triples, fcr:content to work ...

Resolves: https://www.pivotaltracker.com/story/show/60769514
Add streaming RDF to following endpoints

- FedoraIdentifiers now streaming RDF
- FedoraRepositoryNodeTypes now streams RDF
- FedoraRepositoryNamespaces now streams RDF
- FedoraWorkspaces now streams RDF

 Better equals and hashCode for RdfStream
 Resolves: https://www.pivotaltracker.com/story/show/61166142