Implementation for no binary content jcr/xml file system persistence.

Resolves: https://www.pivotaltracker.com/story/show/74702010
Propagate updates from recent fcrepo4 changes in:
  https://www.pivotaltracker.com/story/show/72351918

Resolves: https://www.pivotaltracker.com/story/show/76740082
Removing hard-coded repository URL -- all repository URLs now come from JMS messages (or the reindex servlet's baseURI parameter)
Adding VisibleForTesting annotation, replacing magic numbers with variables for likely webapp/REST API path components