Graeme One addon

Updated again - Any comments or suggestions or criticisms are welcome! Note: This is a work in progress, only level 1, 2 and 3 are done, with some of level 4 completed, which is what I'm working on again. I took a break, it was getting boring lol The secret areas are not configured as "secrets", so they don't register when you find one. I'll have to fix that at some point I guess. This will replace E1M1, E1M2, E1M3 and E1M4 for Doom 1, I've tested it with ZDoom and GZDoom.