Copy the according file from another project (i.e. XCSoar).  This will
allow copying more code more easily.

DSD-over-USB should not be a MPD core format, because it is not a
"natural" format; it is just a temnporary over-the-wire format.  This
format has been implemented in pcm_export, and does not need to be
supported by pcm_convert.

For simplicity, the MPD core should not have to deal with packing.  It
is rarely used, and those plugins that need it should use the
pcm_export library instead.

Eliminate support for reverse endian samples from the MPD core.  This
moves a lot of complexity to the plugins that really need it (only
ALSA and CDIO currently).

This format is unused since the DSDIFF decoder plugin now reverses the
bit order.

Basic support for Direct Stream Digital.  No conversion yet, and no
decoder/output plugin support.

Support for conversion from float to 16, 24 and 32 bit integer
samples.

Reduce the mess with local variables inside switch{}.

Allow more compiler optimizations.

This is easier and more efficient to loop on, because only two
variables get modified (src and dest).

D'oh, we were reading 16 bit integers instead of 32 bit integers!
That caused silence when trying to play a 32 bit input file on a 24
bit sound card (e.g. USB sound chips with 24 bit packed samples).

This patch prepares support for floating point samples (and probably
other formats).  It changes the meaning of the "bits" attribute from a
bit count to a symbolic value.

After we've been hit by Large File Support problems several times in
the past week (which only occur on 32 bit platforms, which I don't
have), this is yet another attempt to fix the issue.

Don't abort the whole MPD process when the conversion fails.  This has
been a denial-of-service attack vector for years.

This updates the copyright header to all be the same, which is
pretty much an update of where to mail request for a copy of the GPL
and the years of the MPD project. This also puts all committers under
'The Music Player Project' umbrella. These entries should go
individually in the AUTHORS file, for consistancy.

Support converting 32 bit samples to any other supported sample
format.

Added code to convert all other sample formats to 32 bit.

There is nothing 24 bit specific in the pcm_dither_24 struct.  Since
we want to reuse the struct for 32 bit dithering, let's drop the "_24"
suffix from the struct name.

Replace a "static" buffer with the PCM buffer library.

The function does not need the full pcm_convert_state struct.

Moved all code which converts the sample format to a separate library.