Reduce header dependencies.

First draft, not really pluggable currently - hard-coded to use the
"simple" plugin, and calls several of its internal functions.

The API is very simple currently, all searches are still performed
over the root "directory" object.  Future changes to the API will move
those search implementations into the plugin, to allow more efficient
implementations, or implementations that don't have the whole tree in
memory all the time.

libOggFLAC has been deprecated for 5 years now, and we havn't been
testing it for a long time.  Let's delete it.

Don't add those to MPD_CFLAGS / MPD_LIBS.

Make the code portable.

.. and destruct the output object properly in test/run_output.

Restore some of the original file structure from from raop_play.

Clean up the process before exiting.

Auto-enable the plugin when OpenSSL was found.

To demonstrate the new I/O thread.  libsoup is well-integrated into
the GLib main loop, which made this plugin pretty easy to write.

As a side effect, we have to initialize the I/O thread in all debug
programs that use the input API.

Try to eliminate the remaining blocking I/O.

Sorts remaining songs by priority.  This can be used for the
much-demanded "queue feature".

Remote Audio Output Protocol (RAOP), for Apple devices.

A bit of automake magic (see info automake "Per-Object Flags").
Compile-tested.

Don't create a modified copy for out-of-tree builds.

Just there to support the "cdio_paranoia" input plugin.

Based on the APE reader.

Generic library for scanning APE tags.  Eliminated one "goto"!

Using libffado, to play on firewire audio devices.

Warning: this plugin was not tested successfully.  I just couldn't
keep libffado2 from crashing.  Use at your own risk.

For details, see my Debian bug reports:

  http://bugs.debian.org/601657
  http://bugs.debian.org/601659

Win32 has many audio APIs. New name is slightly more correct.

I've added PIPE_EVENT_SHUTDOWN because calling g_main_loop_quit() do not work when called from another thread.
Main thread was sleeping in g_poll() so I needed some way to wake it up.

By some strange reason call close(event_pipe[0]) in event_pipe_deinit() hangs.
In current implementation that code never reached so that was not a problem :-)
I've added a conditional to leave event_pipe[0] open on Win32.