- Fixes problem where 60% became 59% due to bad rounding.
- Tests assume scale of 0-65536 which matches ALSA.
- Check all possible values of set_volume and ensure we the right value out.
- GStreamer tests now use this instead of a real mixer.
- fakemixer and the autoaudiomixer still need to be moved.
- We should probably use a fakesink as output as well.
- Moves GStreamer initialization out of on-start as it is not obvious to me how
to stop rest of setup on other ways.
- Note that gst.GError != gobject.GError as far as except is concerned.
