Neo4j improvements

1. Some library cleanup/replacement
2. Refactored the original Graph (Node, Edge) and AttributeHolders into interfaces and used the old ones to implement InMemory versions. The Neo4jGraph is note quite ready yet. Will be the next pull request.
3. The Neo4j Graph allows for quite some flexibility so I moved the config from the command line into a XML. The XML allows you to map properties in the Graph to specific indices. Reasoning: I prefer the config files to cmd line options in a file :)
4. The index mapping was part of the factory class that produces the GraphDatabaseService. That is really not the right way to do.