Simplify the definition of many build options.

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

This encoding plugin features a fixed-point mp3 encoder,
with faster encoding on architectures without a FPU.

Right now the encoder is limited to stereo and 16 bit depth.
The bitrate and sample rate can be modified in audio_output.

audio_output {
        type            "httpd"
        name            "My shine stream"
        encoder         "shine"
        port            "8000"
        format          "44100:16:2"
        bitrate         "320"  # default: 128
}

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.

When using wave encoder with httpd audio output mpd can input this stream via http and audiofile decoder.
This for example opens simple way to configure lossless audio streaming port(like jack or pulseaudio does but without overhead).
Another possibility can be using it for gathering raw data for visualization plugins (If sync issue will be resolved)

This encoder plugin is a replacement for the LAME encoder plugin for
those who prefer a "free" (non-patent encumbered) encoder library.
Most of the plugin source code is copied from the LAME encoder plugin,
since the LAME and TwoLAME APIs are nearly the same.

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.

This new vorbis encoder plugin is based on the existing shout_ogg.c
plugin.

The new generic encoder API will replace shout's custom encoder API.

Don't use libc's rand() function, because it is slow.  Our own trivial
linear congruential generator is good enough for dithering.

redirect_stdin() is a daemonization function, and disconnecting from
the standard input is always a good idea for MPD.

Prepare for the migration to the GLib option parser, which uses
gboolean for flags.