Add option to restore master sound

[dzosz]

There's no way to restore the sound from chobby if game was muted during the game. The usual scenario:

1. I spec the game and I manually reduce volume to 0.0 using adv player list slider.
2. After game ended I can't hear when someone rings me from the lobby.

[FIr3baL]

@Beherith Could you move this over to https://github.com/beyond-all-reason ? My strong guess is, that game is changing the master volume (of whole engine) instead of using a game specific volume. Chobby uses different volume sliders for ring-volume, menu-volume etc., which don't change by ingame volume changes.

[FIr3baL]

Meanwhile i had a short look into beyond-all-reason sound_volume widget. Yes, i'm pretty sure it's changing the master volume, while i see that there is a volume in bar settings called "general". Maybe general is already meant to do this job ?

So i guess this request could result in a more or less big refactoring of how volumes are handled in repo:beyond-all-reason.

Brainstormed example::

1. master_volume can only be changed in bar:settings menu: 0 = everything is muted I imagine a user sets master_volume once after installation to adjust it relative to his other programs. Yes, he could do the same on os-level, where he can control the volume of this recoil_executable. But he would need to tab out first , change it in os, and then tab in again.
   • (imho the best approach would be to directly change the os-volume for this recoil_executable from inside the game instead of having a separate master_volume at all) - but that's on another planet and would redirect this topic to engine devs
2. chobby adds a new slider in chobby:settings, which would change the exact same value of master_volume
3. bar-game introduces a new level between master volume and game effect volumes, lets call it game_volume
4. all game effect volumes are relative to game_volume, which is again relative to master volume
5. Pressing "+" and "-" ingame controls the game_volume instead of master_volume

Example:

• os_sound_device_volume
  • os_volume for recoil_executable
  • master_volume = 80% of os_volume for recoil_executable ( or remove this line and set os_volume instead)
    • chobby_notification_volume = 50% of master_volume
    • chobby_menu_music_volume = 20% of master_volume
    • bar_game_volume = 20% of master_volume
    • bar_battle = 67% of bar_game_volume
    • bar_interface = 83% of bar_game_volume

[FIr3baL]

@lhog Noticed Behe is on vacation, could you move this topic to beyond-all-reason ?