-Introduced class for ClaimToken, backed by UUID's
-Shifted Email to be backed by a Node
-Introduced base classes for Entity's and unique entities
-Shifted Email to Email.java.ignore until can make it usable with new
Email implementation.
-Added execute method to GraphDatabase for Cypher calls (some
abstractions like Unique and Merge are not available in Java and would
rather use Cypher than locks -- and not sure what the key value for
factories should be for relationships).
-Added base definitions for Label and Relationship types.
-Started adding tests for RelationshipFactory.