Fixes sound system to work with archives (use VFS files instead of
POSIX), fixes#1604.
Improves error handling and logging, refs #1594.
Allows sound to be disabled with -nosound/-quickstart runtime options or
--without-audio build option, fixes#1609, #1614.
Experimentally increases default buffer size to help prevent sound
stoppages.
This was SVN commit r12566.