[arch-general] mpd had removed relative volume functionality.

[b4283]

Xavier 提到:
> And do you have some links / references about this?
>   
> And what is the problem doing it in mpc client?
consult to the mpd wiki: 
http://mpd.wikia.com/wiki/MusicPlayerDaemonCommands#volume
stating that "This is a deprecated command, is not recommended for use, 
and may be broken or removed at any time."

I think there's no problem doing this in mpc, you just have to fetch the 
current value from server first, and do the math on the client side 
(just as my script did).

-
b4283