Various changes to redis-benchmark thread and cluster support
Various changes to redis-benchmark thread and cluster support

- MOVED or ASK replies are now handled in cluster mode.
- Only the first slot per node is used in cluster mode.
- Mutlithreading: reduced usage of mutexes in favor of atomic vars.

oranagra/redis,pmem/redis,soloestoy/redis,charsyam/redis,oranagra/redis,ctripcorp/redis,neomantra/redis,neomantra/redis,yossigo/redis,yossigo/redis,yossigo/redis,ofirluzon/redis,pmem/redis,ctripcorp/redis,neomantra/redis,soveran/redis,soveran/redis,charsyam/redis,antirez/redis,yossigo/redis,oranagra/redis,ctripcorp/redis,oranagra/redis,charsyam/redis,antirez/redis,oranagra/redis,ofirluzon/redis,PKRoma/redis,charsyam/redis,antirez/redis,soveran/redis,ofirluzon/redis,PKRoma/redis,pmem/redis,antirez/redis,PKRoma/redis,PKRoma/redis,yossigo/redis,neomantra/redis,soveran/redis,PKRoma/redis,soloestoy/redis,ctripcorp/redis,soloestoy/redis,charsyam/redis,soloestoy/redis,soloestoy/redis,neomantra/redis,ofirluzon/redis,ofirluzon/redis,pmem/redis