DATAGRAPH-340 - Initial draft of CDI Implementation.

Original pull request: #133.
DATAGRAPH-340 - Added shutdown() method to GraphDatabase interface.

Original pull request: #133.
DATAGRAPH-340 - Polished CDI integration.

Changed configuration model to be based on a GraphDatabase CDI bean only. The Neo4jMappingContext and Neo4jTemplate are created internally on the fly now. Upgraded to Javassist 3.18.1 for tests now to make previously failing tests work. Applied some general code, JavaDoc and formatting polish.

Original pull request: #133.