D-Net

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

[maven-release-plugin] copy for tag cnr-enabling-services-2.2.0

[maven-release-plugin] prepare release cnr-enabling-services-2.2.0

added cache layer issn lookups. Lasts 5 min (300 sec) and caches are invalidated each time a subscription is added or removed

using cache for subscription access, added cache manager

using cache for subscription access, more logging

using cache for subscription access