make sure that OBJECT ENCODING returns skiplist for sorted sets, and not raw, so that once we will merge specially encoded sorted sets everything will make sense.

DUMP implemented, RESTORE and MIGRATE fixed. Use zcalloc() instead of zmalloc()+memset() in sds.c when a new string is created with NULL initialization pointer.

fixed memory leak introduced with the previous commit. Many thanks to Pieter Noordhuis for spotting it in no time

Fixed issue #503. MONITOR + QUIT could crash the server, there are actually other interactions that could have the same effect (for instance Pub/Sub).

centralized cluster config file name. Assigned slots in CLUSTER NODES output and in cluster config file.

zipmaps are now endianess agnostic, needed for on disk serialization of zipmaps without convertions layers