[Ohrrpgce] SVN: teeemcee/8415 Add sound effects volume support to backends and allmodex

[subversion at HamsterRepublic.com]

teeemcee
2017-02-19 06:39:23 -0800 (Sun, 19 Feb 2017)
292
Add sound effects volume support to backends and allmodex

Added get/set_sfx_volume allmodex functions. Not used anywhere yet

Also, in the process I've implemented music_setvolume in
music_native/native2. Previously they could only set the volume
of MIDI, and played everything else at 100%.
---
U   wip/allmodex.bas
U   wip/allmodex.bi
U   wip/music.bi
U   wip/music_audiere.bas
U   wip/music_native.bas
U   wip/music_native2.bas
U   wip/music_sdl.bas
U   wip/music_silence.bas
U   wip/whatsnew.txt