New 1.3.0 release which works with 0.20 and uses BulkProcessor

There were a couple of non backward compatible changes with 0.20. I fixed that and while I was at it  I introduced the use of BulkProcessor. It's configurable through a new index.bulk section which allows to specify the number of actions, size, flush interval and concurrent requests.
The pom and the README should be ready for the new 1.3.0 release, I guess you just need to upload the assembly to github.