delete the jackson libs that are replaced by 1.9.6
refactored the Graph and AttributeHolder:
Both are now interfaces (including Graph.Node and Graph.Edge). The previous implementations are now: InMemoryGraph(.InMemoryNode;.InMemoryEdge) and InMemoryAttributeHolder
Due to the change in imports other classes had to be modified. No changes in the logic though!

NOTE:
not fully tested yet!
the Neo4jWriter now takes a config xml file. the file allows for a mapping of properties to indices and outside code selection of the Interaction type. additionally support is added for embedded databases to take a neo4j.properties file to start the db.

the Neo4jFactory uses the supplied config to generate the appropriate db instance. The index lookup should be moved out of it though.
moved the index mapping out of the factory into its own service class.
the factory uses only one instance of the indexer.
Merge pull request #2 from gsummer/master

Neo4j improvements