[mythtv] Audio Update - Another patch

[Ed Wildgoose]

Here is a link to the latest version of my audio patch.  This is an 
interim version and is not for cvs, but mainly so that David and Jesper 
can check what I have done versus their stuff.

http://www.wildgooses.com/downloads/myth_audio2.tar.gz

I have included all the audio files as files, rather than diffs, for 
convenience.  However, diffs available on request (and will be for final 
patch).  Possibly I have missed something from the patch, please just shout.

The main changes in this patch are

- the inclusion of the audio_ca changes
- framework for volume control in place
- arts driver might be fixed (someone please test it)

I would be grateful for general users to test this patch and report back 
on any problems, especially with alsa or any other audio drivers. David, 
would you mind having a look at this volume control code and see if you 
can do anything useful with it (as we agreed privately, best solution 
seems to be a Volume class that the AudioOutput class inherits from, and 
this would provide all the standard junk like muting channels and 
restoring them, etc.).  Jesper could you check that I have your core 
audio patches included correctly.

Thanks

Ed W