OGM-370 Create Neo4jExternalTransactionManager
OGM-370 Use the transaction manager of the applicaiton instead of the one in neo4j
OGM-370 Neo4jJtaPlatform should look for TransactionManager (not TxManager)
OGM-370 Neo4jTupleSnapshot should not throw exception when a node has been deleted
OGM-370 Fix exceptions