Title: Sling Caching Services

Caching services are available as a contribution at [https://svn.apache.org/repos/asf/sling/trunk/contrib/extensions/cache](https://svn.apache.org/repos/asf/sling/trunk/contrib/extensions/cache)

Both EhCache and Infinispan implementations are provided, with good unit and integration tests coverage.

A portal cache provider API implementation is provided, that depends on the whiteboard portal modules
found under [https://svn.apache.org/repos/asf/sling/whiteboard/portal](https://svn.apache.org/repos/asf/sling/whiteboard/portal)