Mark ConcurrentLRUCache cleaner threads as daemon

Also, name these threads "ConcurrentLRUCleaner-" + Thread#getId()
rather than letting them default to compatarively uninformative names
in the standard "Thread-#" pattern.
Fire HZC lifecycle shutdown event on mgr close

This prevents non-daemon Hazelcast background threads from running and
keeping the VM from exiting after all of the Hazelcast cache/store
managers have closed.
Refcount-based embedded Cassandra shutdown logic

The static singleton CassandraDaemonWrapper class now increments a
counter when a start() call is made and decrements it when a stop()
call is made.  When the counter is decremented to zero, the embedded
Cassandra instance is immediately shutdown.
Fix HC close/clearStorage() when manager's closed