Added a new class ShutdownListener which listens for ApplicationContext closed events and shuts-down Ektorp.
Added additional documentation to the ShutdownListener.
Merge pull request #179 from dlvenable/spring_shutdown_listener

Spring shutdown listener
avoid useless json-decoding and json-encoding of rawkeys, they can be kept as-is and passed to the query. This can be a big performance improvement in some cases.
Merge branch 'AvoidUselessDecodingAndReEncodingOfRawKeys' into integration