INT-2980 Jdbc Message Store: Polling Wrong Message

* Add Join to JDBC Query
* Add MySql-specific tests
* INT-2987 - MessageStore MySQL - Support Fractional Seconds
  - Update MySql Connector version to 5.1.24
  - Add DDL scripts for MySql versions 5.6.4 and higher
INT-2980 - Check also for Regions

* Add test
INT-2980/INT-2987 - Add Documentation
INT-2980 - Doc: Add info to What's New Section