Previously, only streams were saved with range and tags, but this is
necessary for all "partial" songs (e.g. CUE tracks).

Works around a build failure on Solaris because annoyingly, Solaris
reserves the name "queue".  This rename was pending anyway.

From now on, struct Song will be used by the database only, and
DetachedSong will be used by everybody else.  DetachedSong is easier
to use, but Song has lower overhead.

Replaces GLib's g_str_has_prefix().

Don't use IgnoreError() when there's an overload that does not try to
give us one.

Fix for a major memory leak.

Prepare to migrate away from GLib.  Currently, we're still using GLib
as a backend.

Replaces GLib's GError.

Use the C++ API.

Allow the plugin to allocate the GetSong() return value.

Use the functions song_save() and song_load() to use the same format
as in the database file for those songs which need the tags.

Don't try db_get_song() if the URI has a scheme.

The only caller doesn't use its return value, and the value isn't
useful anyway.

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.