Normalized error returns to be undefined or contain a value (no longer mixes undefined and null).
Added unit tests for objectId() and Metadata within Persistence.
Revised personas unit tests since error normalization has occurred.
Covered persistence service that deals with data collections with unit tests.
Removed unnecessary items from config.
Updated mock data store to be consistent with the mongo store when dealing with errors.
Covered persistence drive in unit tests.
Merge pull request #52 from ozone-development/persistence-unit-tests

Persistence unit tests