Quadra

When you set the ppmlimit, it will drop anyone who gets
a score of over 4*ppmlimit after 4 minutes of gameplay.
So for example if you after 10 minutes gameplay reach a
score of 4*ppmlimit, you get dropped, even though the
ppm is still under the limit.
So instead of checking (playing_time >= 24000 && score
> 4*ppm_limit), it should be something like (playing_time
>= 24000 && score*6000 > ppmlimit*playing_time) in
net_list.cpp.