Adding commands to SLAVEOF and CONFIG (GET/SET/RESETSTAT) to finagle redis

This PR adds the commands SLAVEOF and CONFIG to finagle redis. Also included is a fix for an issue where byte arrays were converted to strings before sending to redis. Byte arrays when converted to string in this manner used the jvm default character, resulting in different byte strings for what should be the same key. (what you want is the raw bytes you put in, but what you got was this weird thing of "bytes you put in, converted to default charset and then back again")