[Bug 34638] Gnome Volume Control applet should display "digital output" switch

[Leo Gomez]

Public bug reported:
https://launchpad.net/malone/bugs/34638

Affects: gnome-media (Ubuntu)
       Severity: Normal
       Priority: (none set)
         Status: Unconfirmed

Description:
In order for someone with digital speakers to get their speakers to
produce sound, they have to open a terminal, run alsamixer, and enable
the proper option.

This option would be much easier to discover if displayed under the
'Switches' tab in Gnome Volume Control, as opposed to scrolling though
the dozens of options in alsamixer (a new user might not even know to
use alsamixer).