Conflicts:
	src/decoder/ffmpeg_decoder_plugin.c
	test/read_tags.c
	test/run_decoder.c

Implements support for libavcodec 0.9, which removes the compatibility
macros SAMPLE_FMT_*

Minor optimisation.

Use the tag_item_names table to look up the names of all MPD tags, and
remove the duplicate entries from ffmpeg_tag_maps.

Allow using this function without the ffmpeg_tag_map struct.

Eliminate some duplicate code.

Move the #ifdefs out of _copy_metadata().

No interest in this return value.

Reduce the number of lock/unlock cycles, and make database handling
safer.

This was the cause of the reversed ordering when loading a database
file.

It seems gcc 4.5 does not allow #pragma within function:

 src/input/soup_input_plugin.c:284:9: error: #pragma GCC diagnostic not allowed inside functions

This commit fixes a major regression in directory_lookup_directory(),
which broke the deep lookup of directories.

Wrap songvec_find() and other songvec methods.

Random access is not needed, and a linked list is easier to manage: we
don't need to (re-)allocate the pointer array.

Pass only the "name" to a directory, instead of the full (relative)
path.

This overhead is completely useless, because no caller expects this
behaviour.

The given song must exist, or MPD will abort.  Calling it with an
unknown song is illegal.

Conflicts:
	src/decoder/ffmpeg_decoder_plugin.c

Require libavutil 51.5.0.

This function was added when the libavformat version was 53.2.0, but
the actual release 53.2.0 did not have it.

Use libasound's polling functions, implement a bridge to GSource /
GPollFD and send idle events to clients when an external program
changes the ALSA mixer volume.

Better error handling.

Conflicts:
	src/decoder/ffmpeg_decoder_plugin.c
	src/input/ffmpeg_input_plugin.c