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
changelog for 1.4.2
[maven-release-plugin] prepare release org.ektorp.parent-1.4.2
[maven-release-plugin] prepare for next development iteration
just a refactoring : moved Attachment related stuffs to new class StdAttachmentCouchDbConnector. Existing methods now just delegates to it.
extended AttachmentCouchDbConnector in order to support Apache HttpEntity, providing a way for user applications to save an Object directly in a streamed way without relying on temporary ByteArrayOutputStream+ByteArrayInputStream, just by implementing an appropriate HttpEntity