[mythtv] Audio update with volume

[David George]

This further expands on the big audio update.

This patch includes all of Ed Wildgooses's changes that he posted 
yesterday except for the GetVolumeChannel, SetVolumeChannel, 
SetVolumeAll code.  I also included Jeremiah Morris's thread patch which 
provides the groundwork for separating push audio methods (OSS/ALSA) 
from pull audio methods (Jack?/Mac CA).  I also looked at Jesper 
Sorenson's ALSA patch and incorporated the no-close on error (most of 
the other changes were already in there).

This is against CVS as of today.  The diff may look a little strange 
because as far as I can tell cvs diff doesn't support -N for new files, 
so I checked out a fresh copy of CVS and did a diff -Nura on the two 
directories.

Here is the link:

http://www.onyxsoft.com/mythtv/audio-volume.tar.bz2

The only two changes required to existing code outside of the 
libmyth/(audio,vol}* files are libmythtv/tv_play.cpp and 
mythmusic/playbackbox.cpp to support the new volume control.

Don't let the 312k download scare you.  Most of that is the inclusion of 
libsamplerate which I modified to compile in the Myth framework.
--
David