Use jack_set_info_function() to install an info callback.  Don't let
libjack print them to stderr.

When we do not explicitly catch G_IO_ERR and G_IO_HUP, GLib can go
into an infinite loop, because it won't deliver the socket error to
MPD.

When there are duplicate slashes in the song paths, eliminate them;
example:

 /var/lib/mpd/music//foo.mp3

becomes:

 /var/lib/mpd/music/foo.mp3

The slash is only detected at the border between the music_directory
and the local part.

When the user configures a music_directory with a trailing slash, it
may break playlist loading, because MPD expects a double slash.  Chop
off the trailing slash.

ffmpeg_tag_internal() does not look for a few tags that mpd
supports. Most noteably:

 comment -> TAG_ITEM_COMMENT -> Description
 genre -> TAG_ITEM_GENRE -> WM/Genre (not WM/GenreID)
 year -> TAG_ITEM_DATE -> WM/Year

I *think* that this is the last of the tags that AVFormatContext() in
ffmpeg supports that mpd also uses.

Make those two methods optional to implement, and let input_stream.c
provide fallbacks.  The buffer() method will be removed one day, and
there is now only one implementation left (input_curl.c).

The open_stream() method opens the input_stream.  This allows the
archive plugin to do its own initialization, and it also allows it to
use input_stream.data.  We can remove input_stream.archive now, which
was unnatural to have in the first place.

This way, plugins can manipulate the plugin pointer during open().

MMS streaming is experimental; sync the default value with the help
text.

Return false from mpd_jack_play(), let the MPD core close the device.

Don't leave uninitialized bytes in the jack_data struct.

When MPD stops playback, close the JACK client connection.

The "bps" attribute is calculated, but never used.

Return true/false instead of 1/-1.

Preparation for supporting other channel numbers than stereo: use
loops instead of duplicating code for the second channel.  Most
likely, gcc will unroll these loops, so the binary won't be any
different.

When jack_get_ports() returns NULL, we cannot have any ports to
connect to, and the device cannot play anything.

libjack's jack_port_name() function returns the effective port name,
we don't need to do it manually.

Do the global libjack initialization in the global plugin
initialization function.

This patch implements the MMS protocol, by using libmms.  It is quite
experimental: it does not support seeking yet, and it is currently
using synchronous I/O, which causes MPD to hang while waiting for the
server.

When the playlist is cleared, pc.errored_song is also cleared.  This
causes pc_errored_song_uri() to crash, because it assumes that
pc.errored_song is set.  Reset pc.error to fix that assumption.

Moved people who havn't contributed during the 0.14 development cycle.

When waiting for free space in the ring buffer, the JACK plugin
sleeped 10ms until there is enough space.  This delay was too large
for low-latency setups (<10ms), and created a lot of xruns.  Work
around that by reducing the sleep time to 1ms.

A proper solution for this would be to use an event based approach,
and we will do it, just not now.

When the connection failed once, you had to restart MPD, because it
never cleared the jack_data.shutdown flag.  Instead, it refused to
play anything "because there is no client thread" (which is wrong at
that point).

If the ring buffers are allocated after jack_activate(),
mpd_jack_process() might segfault because it attempts to access them.

Call jack_port_register() before jack_activate().

The variable "serviceName" is initialized with SERVICE_NAME, but was
overwritten with NULL when the setting is not configured.

GIOChannel is more portable than raw read()/write() calls.  We're
using GIOChannel anyway, because we need it for plugging the client
into the GLib main loop.

Configure the GIOChannel to the bare minimum: no character set, no
buffering.

Use g_io_channel_win32_new_socket() instead of g_io_channel_unix_new()
on WIN32.

This variable doesn't have a role since 80799fa8.

http://xkcd.com/292/

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.

Create a HTML chunk of each DocBook chapter.  Use the UTF-8 character
set instead of docbook-xsl's ISO-Latin-1 default.

The mixer plugins should re-use the mixer struct and incorporate it in
their object class.

Both methods are always called together.  There is no point in having
them separate.  This simplifies the code, because the old configure()
method could be called more than once, and had to free old
allocations.

Those have been superseded by the new legacy configuration code.

Reimplemented the legacy mixer configuration: copy the deprecated
configuration values into the audio_output section.  Don't configure
the mixers twice (once for the audio_output, and a second time for the
legacy values).

This requires volume_init() to be called before initAudioDriver().