plasma volume alpha1

[Harald Sitter]

http://people.ubuntu.com/~apachelogger/src/plasma-volume-0.50.0.tar.xz

As previously noted in plasma meetings it's time for some testing of
the volume applet. The objective here is to get some testing of the
underlying library going until the UI gets finalized.

It does:
- contain a lib to sit on top of pulse
- requires a Qt with glib to work (just like phonon does fwiw)
- reimplement pavucontrol almost entirely as a KCM
- provide a plasma applet to control the volume

The applet is intentionally only offering very limited functionality. Namely:
- wheeling to control volume of all outputs at the same time
- middle clicks to mute all outputs at the same time
- sliders to control the volume individually

The reason it is limited is because we have not reached a final UI
design which is very much my fault, but no sense in holding software
hostage over it.

If you want to use the git version directly:
http://quickgit.kde.org/?p=scratch%2Fsitter%2Fplasma-volume-control.git

Bug reports can be hurled at me in whatever fashion you deem useful
(IRC, email, proper mail, FAX)

Design input should go here:
https://forum.kde.org/viewtopic.php?f=285&t=122399

I do plan to have it available for installation in one of next weekly
ISOs (possibly only after Plasma 5.3 release for organizational
reasons).

# Errata
- when scrolling over a list of volume-things the scrollbars
themselves also still receive the wheel event
- input devices and output devices can not really be told apart in the
applet's popup dialog
- applet tooltip doesn't say anything useful
- changing the output via the KCM does override category and priority
settings from Phonon (this is actually a general thing with pulseaudio
that is currently not visually represented anywhere)
- there is no unit testing of anything as I have yet to come up with a
plan on how to actually test the pulse-adjacent bits without using the
proper pulse socket and the UI is changing like twice a day anyway.

HS