Fixed some clientside lag when firing weapons

Removed some legacy code that could have been causing significant lag on
low end systems when firing guns.
Fixed MG sound

Fixed MG sound not playing.
Made RAC sound stutter a bit less.
Merge remote-tracking branch 'remotes/upstream/master'

Conflicts:
	lua/autorun/acf_globals.lua
	lua/effects/acf_muzzleflash/init.lua
new readme