Merged ZREVRANK from Pietern

diff --cc redis.c
index 3c1408f7fd95296de693bf18ee73d9fa906b675e,c882694dd34d27481c921b1e48cca488c73560b2..c1777c761931b29a2e56d85e4b810b253f8ffc40
--- 1/redis.c
--- 2/redis.c
+++ b/redis.c
@@@ -5668,7 -5583,15 +5674,15 @@@ static void zrankGenericCommand(redisCl
      }
  }
  
 -/* ==================================== Hash ================================ */
+ static void zrankCommand(redisClient *c) {
+     zrankGenericCommand(c, 0);
+ }
+ 
+ static void zrevrankCommand(redisClient *c) {
+     zrankGenericCommand(c, 1);
+ }
+ 
 +/* =================================== Hashes =============================== */
  static void hsetCommand(redisClient *c) {
      int update = 0;
      robj *o = lookupKeyWrite(c->db,c->argv[1]);