SuperFollow goes down without need

[frbaroni]

procedure TBBotSuperFollow.OnCreatureWalk(ACreature: TBBotCreature; APrevPos: BPos);
 begin
   if (FCreatureID <> 0) and (ACreature <> nil) then
     if ACreature.ID = FCreatureID then
       if APrevPos.Z = 7 then
         BBot.Cavebot.GoFloorDown(APrevPos);
 end;

We need more protections before going down, like ensuring the FCreatureID is non longer in the battlelist. The way it is currently, it will always go down.