D-Net

added mvc controller method to clear the OAI caches: oai/clearCaches.do

[maven-release-plugin] prepare for next development iteration

[maven-release-plugin] copy for tag dnet-oai-utils-3.3.0

[maven-release-plugin] prepare release dnet-oai-utils-3.3.0

Cache management: it's a mess if we have more than one <cache:annotation-driven> instructions:
- the container now has a dedicated application context for caches
- logs to DEBUG for spring cache module

reverted to revision 38450