Tweaked for vanilla compatibility by Catoptromancy,
who wrote in <http://www.doomworld.com/vb/post/963232>:
>Tried really hard on mech1 but it is way too open. There are many
>places in the map that can see to other side. Only way to cure the
>massive HOM was to make those 4 ledges to be walls to block sight. A
>few other areas were also slightly gameplay touched to get rid of tons
>of linedefs.
>Mech7 was much more closed and I could leave much more detail. Still
>had to get rid of ceiling lights or simplify them. Mostly just squared
>corners and got rid of step borders.
Signed-off-by: RjY <rjy@users.sourceforge.net>
