when processing gossip packets make sure to also update the node bitmap when associating slots to nodes. Fixed simply using the appropriate helper function to add a slot.

Clear the importing status from the slot if a CLUSTER SETSLOT command permanently assigns the slot to the importing node.

rioInitWithFile nad rioInitWithBuffer functions now take a rio structure pointer to avoid copying a structure to return value to the caller.

Fixed semantics of CLUSTER SETSLOT, SELECT now only denied in cluster mode if selected DB is not 0 so that MIGRATE still works well.

evaluate cluster state after config load. Still bugs in the slot allocation after nodes config load to fix.

when loading config set the ping/pong timestaps to the current value. Even a node in FAIL state can be accepted again if there are no slaves for this node so election was not possible

fixes to configuration loading and saving. However there is to still fix the logic for reconnection/behavior of nodes after a restart.

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.