Upgrade to Neo4j 2.0 - new module blueprints-neo4j2-graph

* adapted API and SPI changes
* added label support for Neo4jVertex
* added minimal Cypher support to Neo4jGraph (mostly for schema index operations)
* fixed blueprints-tests by adding an constantly open outer transaction which is also restarted after commit or rollback in Neo4jTestGraph
added Neo4j2 graph support via Michael Hunger pull request.