Make SinkPlayer methods to get volume and mute return failure when
called on an unknown sink.

Change-Id: I7491b913c6a851d0b97ec28eacf06a987496dd71
AJAUDIO-2: Use "default" ALSA device and mixer instead of specifying
"plughw:0,0" and "hw:0" in the SinkService.

This lets the mixer controls work properly on Ubuntu.  Specifying the
device and mixer can still be done with the -D and -M options to
SinkService.

Change-Id: I3f8d2062faacbe07a10e93e5b9e54c454e1faca8
AJAUDIO-28: Don't read past the DATA section in the WAV file.

Some WAV files include additional chunks after the PCM data.  The code
assumed that was not the case.

Change-Id: I88a476468cb8f5fc488d20ad50a0090a3ac65f35