Make sure we get a UTF-8 encoded string.

Pass audio_output objects around instead of void pointers.  This will
give some more control to the plugin, and prepares for non-blocking
audio outputs.

Move the "extern" declarations from output_list.c, for more type
safety.

Version 1.0.0 of the libao library added a new field to the
ao_sample_format struct.  It is a char * named matrix.  When
an ao_sample_format is allocated on the stack, this field contains
garbage.  The proper course is to insure that is initialized to NULL.
NULL indicates that we do not want any mapping.
The struct is now initialized using a static initializer, and this
technique is compatible with all known versions of libao.

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.

Use GLib's GError library for reporting output device failures.

Note that some init() methods don't clean up properly after a failure,
but that's ok for now, because the MPD core will abort anyway.

Renamed functions and variables.

The MPD core guarantees that the audio_output object is always in a
consistent state: either open or closed.  When open, it will not call
the open() method again, and when closed, it will not call play().
Removed several checks and the NULL initialization.

The method is empty, and we can simply set the method pointer to NULL
instead.

audio_output_get_name() has been removed, which was the only function
left in output_api.h.  The output plugin doesn't need the audio_output
object at all, remove the parameter from the init() method.

Use config_get_block_string("name") instead of audio_output_get_name().

The meaning of the chunk depends on the audio format; don't suggest a
specific format by declaring the pointer as "char*", pass "void*"
instead.

The old API required an output plugin to not return until all data
passed to the play() method is consumed.  Some output plugins have to
loop to fulfill that requirement, and may block during that.  Simplify
these, by letting them consume only part of the buffer: make play()
return the length of the consumed data.

writeSize is a memory size and its type should thus be size_t.  This
allows us to remove two explicit casts.

On some platforms, g_free() must be used for memory allocated by
GLib.  This patch intends to correct a lot of occurrences, but is
probably not complete.

All config_get_block_*() functions should accept constant config_param
pointers.

Eliminate some more getBlockParam() invocations.

This replaces lots of getBlockParam() invocations.

Renamed functions, types, variables.

g_strsplit() is more portable than strtok_r().

Use GLib's G_GNUC_UNUSED instead of gcc.h's mpd_unused.

There have been bug reports on MPD regarding 24 bit output via
libao/esd.  The "ao" plugin does not attempt fall back to 16 bit
currently, and thus fails to play 24 bit audio (i.e. all mp3 files).
Make it always use 16 bit samples for now, until more bits are
well-tested.

When ao_open_live() failed, MPD would ignore the error code in
"errno".  Make it print a meaningful error message.

The function audioOutputAo_error() did not implement all possible
libao error codes.  Support the rest of them, and fall back to
strerror().

When an output plugin fails to play a chunk, close it.  This replaces
various manual close() calls in nearly all plugins.

Don't return 0/-1 on success/error, but true/false.  Instead of int,
use bool for storing flags.

Don't compile the sources of disabled output plugins at all.

Again, no CamelCase in the directory name.

The last bit of CamelCase in audio_format.h.  Additionally, rename a
bunch of local variables.

The old struct initializers are error prone and don't allow moving
elements around.  Since we are going to overhaul some of the APIs
soon, it's easier to have all implementations use C99 initializers.

We have eliminated direct accesses to the audio_output struct from
the all output plugins.  Make it opaque for them, and move its real
declaration to output_internal.h, similar to decoder_internal.h.

Pass the opaque structure to plugin.init() only, which will return the
plugin's data pointer on success, and NULL on failure.  This data
pointer will be passed to all other methods instead of the
audio_output struct.

Reduce direct accesses to the audio_output struct from the plugins:
this time, eliminate all accesses to audio_output.name.  The name is
required by some plugins for log messages.

Since the output plugin returns a value indicating success or error,
we can have the output core code assign the "open" flag.