[These symbols were removed in libudev.so.1.0.0. Replace them with
hardcoded strings. -- heftig]
Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>
Completely rework mixer logic. This now allows controlling a full set of
elements from a single sink's volume slider/mute button.
This also introduces sink and source "ports" that can be used to choose
different input or output ports with the UI. (i.e. "mic"/"line-in" or
"speaker"/"headphones".
The mixer paths and device maps are now configered in external
configuration files and can be tweaked as necessary.