PrBoom: a Doom port merged with LxDoom and LSDLDoom
        based on BOOM, a modified and improved DOOM engine

Copyright (C) 1999 by
  id Software, Chi Hoang, Lee Killough, Jim Flynn, Rand Phares, Ty Halderman

Copyright (C) 1999-2000 by
  Jess Haas, Nicolas Kalkhof, Colin Phipps, Florian Schulze

Copyright (C) 2005, 2006 by
  Florian Schulze, Colin Phipps, Neil Stevens, Andrey Budko

Copyright (C) 2007 by
  Andrey Budko, Roman Marchenko

Copyright (C) 2011 by
  Nicholai Main

Copyright (C) 2015 by
  Charles Gunyon

