ISPN-2806 Karsten's Faster FileCacheStore implementation

* This CacheStore implementation stores cache values in a single file,
and keeps keys and file positions in memory. Max memory consumption
can be controlled via a maxEntries parameter.
* Always keep on-disk state up to date: Write changes to disk
immediately, including the cache keys. On startup, the state of the
cache store can be restored by scanning the entire file.
* Clean shutdown (storing the in-memory index on stop()) is no longer
required for persistence.

Signed-off-by: Karsten Blees <blees@dcon.de>
ISPN-2806 Rename Karsten's file cache store and add configuration

* Renamed the cache store to a more meaningful name.
* Added new style configuration and configuration builder classes.
* Modified parser to deal with new single file cache store.
* Added tests that verify single file cache store configuration.