Fix for MULTI/EXEC and Replication/AOF: now the block is correctly sent as MULTI/..writing operations../EXEC. Ok for slaves but more work needed for the AOF as it should be a write-all-or-nothing business

Added package require Tcl 8.5 in redis.tcl so it will show a clear error when the test suit is attempted to run under 8.4

Added support for Guru Mediation, and raising a guru mediation if refCount <= 0 but decrRefCount is called against such an object

make sure that cmpobj is in decoded form when sorting by ALPHA (this solves edge case from previous commit where (!sortby && alpha) == 1)

set refcount of string objects retrieved from zipmaps to 0, so we don't have to touch the refcount of the objects inside dicts

Incrementally rehahsing hash table! Thanks to Derek Collison and Pieter Noordhuis for feedbacks/help