1.007 - Revert changes in 1.006 - need to change to suit the new
Elasticsearch API.
1.006 - Replace ElasticSearch with Elasticsearch
1.005 - Not available for perl version < 5.10
1.004 - Faster sessions renamed "lazy"
1.003 - Add support for faster sessions (don't hit ES for every
get or set - just once for each retrieve & flush cycle
0.008 - Added signing of the session ID to make it tamper-proof
0.001 - 0.007 - Formative stuff.