Newcommands fixes #18

new Del,Dump,Expireat,Rename,Renamex,Role,Rpop,Rpoplpush,Rpush,Rpushx,Sadd,Scard,Sdiff,Sdiffstore,Select,Setbit,Setrange,Time,Ttl, and Type commands

modification of Get, Set, Setnx commands as well as Protocol.java and Redis2TextProtocol.java