Rename struct Encoder to PreparedEncoder, and add a new (abstract)
class Encoder which represents one encoder instance.

The old struct config_param remains only for top-level string options.

.. and move the plugins to src/encoder/plugins/.

The MPD core will add this as a prefeix.

Replaces GLib's GError.

Don't deinterleave manually, don't allocate memory.

When you don't explicitly set an output sample rate, liblame tries to
guess an output sample rate from the input sample rate.  You would
think that this "guessing" consists of just setting both equal, but
that is not the case.  For 44.1kHz at 96kbit/s, liblame chooses
32kHz.  This patch explicitly configures the output sample rate, to
stop the bad guessing.

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.

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.

This new LAME encoder plugin is based on the existing shout_mp3.c
plugin.