Redis 2.8 support!
Improvement: Check the new return value of TTL command (starting with Redis 2.8 the command returns -2 if the key does not exist)
Improvement: Rediska_Connection_Exec_Exception message now contains error prefix (starting with Redis 2.8 many errors are prefixed by a more specific error code instead of the generic ERR, for example WRONGTYPE, NOAUTH)