Allow spop to return multiple members

Author: epaulbz

lib/redis/set.rb

@@ -27,8 +27,8 @@ def add(value)
     end
 
     # Remove and return a random member.  Redis: SPOP
-    def pop
-      unmarshal redis.spop(key)
+    def pop(count = nil)
+      unmarshal redis.spop(key, count)
     end
 
     # return a random member.  Redis: SRANDMEMBER