TNDMEXIT - a couple of cooperative Deathmatch exits

People were discussing cooperative Deathmatch exits, i.e., nobody ends the
level until everybody agrees.  Here are a couple of simple ones, for two
and three players respectively.  You can easily generalize the concept to
four players, although I doubt whether many foursomes would really insist
on unanimity before an exit! :-)

Replaces E2M1.  Note the thickness of the sector "guarding" the exit
switch, that's necessary in order to keep people from pressing it
"through" the wall - interesting discovery.  Enjoy, and use the designs at
will.  -- TN
