No more CD player emulation.  The current behaviour of "previous" is
difficult for a client to predict, because it does not definitely know
the current position within the song.  If a client wants to restart
the current song, it can always send "playid".

Renamed all playlist functions to non-CamelCase.

Those were only wrappers for playlist_state_{save,restore}().  Since
sf_callbacks has been removed, we can call the latter functions
directly.

To determine whether to rewind the current song or to go to the
previous song, use a GTimer instead of manually diffing time(NULL).

Consume mode removes each song played

When single mode is enabled, after current song it stops playback,
or it replay same song if repeat mode is activated.

The smartstop feature is a way to tell mpd to stop playing after
current song.
This patche provides:
- 'state' command returns 'smartstop' state (1 or 0)
- 'smartstop' can activate or not the smartstop state
- when song is terminated, mpd stops playing and smartstop is set to 0

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.

This command shuffles a range of songs.

In random mode, this patch allows clients to see the "next song" in
the queue.

Pass constant playlist objects to functions which do not modify it.

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.

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.

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.

The LocateTagItem objects are not modified.

The playlist.c source is currently quite hard to understand.  I have
managed to wrap my head around it, and this patch attempts to explain
it to the next guy.

All callers pass false.  Don't bother to collect that parameter.

There were only two possible states: STOP and PLAY.  The code looks a
lot easier if we use a bool instead.  Move the variable into the
playlist struct.

Added several comments.

Attempt to untie the playlist.c knot: moved the playlist storage code
to queue.c, struct queue.

Don't attempt to restart the player if it was stopped, but there were
still songs left on the playlist.  This looks like it has been a
workaround for a bug which has been fixed long time ago.

The "TAG" event is emitted by the player thread when the current
song's tag has changed.  Split this event from "PLAYLIST" and make it
a separate callback, which is more efficient.

A song index cannot be negative.  Also require the second parameter to
be valid.

Loosely based on a patch provided by lesion in bug #1766. The playlistinfo
command can now retrieve ranges of the playlist. The new argument indicates
which entry is the last one that will be displayed. The number of displayed
entries may be smaller than expected if the end of the playlist is reached.

Previous usage:
playlistinfo [start]

New usage:
playlistinfo [start[:end]]

Don't call command_error() if loading a song from the playlist fails.
This may result in assertion failures, since command_error() may be
called more than once.

There are no unix sockets on WIN32, and therefore no authentication.
WIN32 might have similar capabilities, but until we implement them,
disable that MPD feature.

When the tag of the current song changes (e.g. a new tag was sent in
the stream), update the playlist, so clients pick up the new tag.

Added the function map_spl_utf8_to_fs() which replaces
utf8_to_fs_playlist_path().