import r1254, simplify firesky code

r1254 | svkaiser | 2014-01-25 17:52:45 -0800 (Sat, 25 Jan 2014)

+ Cleaning up fire sky code
import 1255, remove damagescale and healthscale

r1255 | svkaiser | 2014-01-25 18:16:09 -0800 (Sat, 25 Jan 2014)

+ Removed health and damage scale variables
+ Save and restore gameflags and compatflags when returning from a demo
playback
r1256 plus reformatting changes

r1256 | svkaiser | 2014-01-26 12:41:44 -0800 (Sun, 26 Jan 2014)

+ Fallback to lower depth/buffer settings if can't initialize OpenGL
remove iwad checks (r1259)

r1259 | svkaiser | 2014-01-26 13:13:15 -0800 (Sun, 26 Jan 2014)

+ Removing iwad checksum checks. Too much of a hassle to continue
supporting