Allow !join to vote for a game mode even if already playing

modules/wolfgame.py

@@ -1228,7 +1228,7 @@ def join_player(cli, player, chan, who = None, forced = False):
 
     elif player in pl:
         cli.notice(who, "{0}'re already playing!".format("You" if who == player else "They"))
-        return
+        return True
     elif len(pl) >= var.MAX_PLAYERS:
         cli.notice(who, "Too many players! Try again next time.")
         return