Poroposed changes to batch-importer

Hi Michael,

First thanks for developing this tool for importing into neo4j. We are using the database in our new product development and the tool you have developed is going to be very helpful!

I raised an issue about the automatic indexing and a colleague of mine (bcorpusjr) identified some improvements in two java files

src/main/java/org/neo4j/batchimport/Importer.java
src/main/java/org/neo4j/batchimport/importer/AbstractLineData.java

We made a change to the index that is used, added index flushing and changed the logic of when you indicate all rows have been imported. 

This seems to work for us (our imports are now good and displaying as expected in neo4j).

We are not sure why the Lucene index is not working however which is frustrating. We hope that the work we have done will prove useful to you.

I have also updated the documentation on the README.md file.

Hope this proves useful. It would be good to chat about how we use neo4j in our product offering; we are genuinely passionate about this database technology and see a very bright future for it. We believe we have identified novel uses of the technology and would like to discuss sometime if you like?

Kind Regards,

Gerard