Bugfix, Handling edge cases with getRangeFrom/To

Hadn't handled the case where given timestamp is either > or < than the
max or min timestamp in the cache.
Finishing all GET* commands. PING supported added

* GETALL GETFROM GETTO ... DONE!
* PING replies with PONG now
Request handler is done (?)

* ADD MOD DEL added
* ALLOCATE changed to ALLOC
Changes to clients, this will go soon

Needs to be replaced by a threaded test bed of sorts.