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

Allocate a player_control object where needed, and pass it around.
Each "client" object is associated with a "player_control" instance.

This prepares multi-player support.

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.

Renamed all playlist functions to non-CamelCase.

The move command now accepts a range for the first argument, in the same
form as other range commands, e.g. move 15:17 3.  The first song in the
range is placed at the destination position. Note that as with other
range commands, the range is inclusive on the left only; this example
would move only songs 15 and 16, not 17.

[mk: fixed signed/unsigned warnings; use G_MAXUINT instead of
UINT_MAX]

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.

"ls" is a bad name for a library which parses URIs.  We'll move the
rest of the "ls" library later.

This command shuffles a range of songs.

When MPD is stopped, but the last song is still the "current song",
and you delete it, playlist->current is not updated, and becomes an
invalid value.  Fix this by catching "!playlist->playing &&
playlist->current == (int)songOrder".

Moved functions for playlist editing (append, delete, shuffle, move)
to playlist_edit.c.

Moved handlers for control commands (play, stop, next, prev) to
playlist_control.c.

Don't call syncPlaylistWithQueue() in nextSongInPlaylist() and
previousSongInPlaylist().  This is a relic from the time when there
was no event, and was a workaround to the timing problem.

Export the "g_playlist" variable, and pass it to all playlist
functions.  This way, we can split playlist.c easier into separate
parts.  The code which initializes the singleton variable is moved to
playlist_global.c.

Moved everything related to saving or loading the playlist from/to the
state file to playlist_state.c.

Before every operation which modifies the playlist, remember a pointer
to the song struct.  After the modification, determine the "next song"
again, and if it differs, dequeue and queue the new song.

This removes a lot of complexity from the playlist update code, and
makes it more robust.

This fixes an assertion failure: when the last song in the playlist
was playing, and you deleted it, MPD aborted.

Both are unused.

This function shuffles the last song of a range.  This is used by
addSongToPlaylist().

Don't declare and export variables specific to stored playlists in
playlist.c/playlist.h.

Now playlist.c does not contain any protocol specific code anymore.

No CamelCase and no typedefs.

Replaced several wrapper functions from playlist.c, and make command.c
use the queue print functions directly.

To allow code outside playlist.c to access the "queue" object,
provide a function which returns a const pointer.

No typedefs.

Moved the 2 remaining global variables into the playlist struct.

When the playlist was loaded from the state file, the order numbers
were the same as the positions.  In random mode, we need to shuffle
the queue order.  To accomplish that, call setPlaylistRandomStatus()
at the end of readPlaylistState(), and do a fresh shuffle.

song_id_to_position() is only a wrapper for queue_id_to_position().

When MPD is not playing while in random mode, and the client issues
the "clear" command, MPD crashes in stopPlaylist(), or more exactly,
in queue_order_to_position(-1).  Exit from stopPlaylist() if MPD isn't
playing.

Create a new library which saves/loads the queue to/from the state
file.

PlaylistInfo() (notice the capital 'P') sends a stored playlist to the
client.  Move it to a separate library, where all the code which glues
the playlist and the MPD protocol together will live.

Moved protocol printing functions which operate on the queue to
queue_print.c.