levels: new E2M5 from Z0k

[ RjY: changes to submitted version:
- increase gap between pile of crates (sector 256 etc.) and nearby
  walls, to prevent player getting stuck
- set passuse flag on lines 75, 208, 288, and 1320 to stop them blocking
  doors (lines 72, 1348) from being opened
- move monster teleporters so monsters don't have to walk away from
  player to teleport, to prevent excessively long teleport times ]

DW: http://www.doomworld.com/vb/post/1221430
Signed-off-by: RjY <rjy@users.sourceforge.net>