Oops, wvulwind is played when chaingun stops
Let cgame set music volume in S_StartBackgroundTrack

Can set volume for intro and loop.
Add g_syscalls.h to Code::Blocks
Move music defs from engine to cgame

Missing ability to set music volume right now though.
Merge remote-tracking branch 'spearmint/master' (+note)

Now music defs can set music volume again.

Conflicts:
	code/cgame/cg_main.c
	code/client/snd_dma.c
	code/client/snd_openal.c