Handle sound system errors more gracefully

[historic_bruno]

I've added some logging to the new sound system so at least we can see if the OpenAL device init fails, but it will eventually lead to a null pointer dereference and crash since there's minimal error checking in place. In general the errors need to be more descriptive and the error conditions handled more gracefully.

[stwf]

this is much improved by the path in fix 1604

​http://trac.wildfiregames.com/ticket/1604

[ben]

In 12566:

Sound system patch by stwf:
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.

[stwf]

This should be fixed now

[Kieran P]

Marking as fixed. Please reopen if the problem reoccurs.