Track Info [Playlist] field: Add playlist name

For any selected track that is part of a playlist,
additional info about the list is now provided in
the [Playlist] field of the Track Info screen.

1) Asterisk indicates if playlist has been modified.
2) Playlist filename is visible, unless the current
playlist is *not* associated with a file on disk, in
which case the following will be shown instead:

- (Folder)    for unmodified folder playlists.
- (Dynamic)   for playlists that are neither associated
              with a playlist file, nor with a folder.

Change-Id: I9dcf7cbba4ac2e37b23413180a2b2bf4bbe5ee2a

apps/playlist_viewer.c

@@ -523,7 +523,7 @@ static enum pv_onplay_result show_track_info(const struct playlist_entry *curren
     }
 
     return id3_retrieval_successful &&
-            browse_id3(&id3, current_track->index + 1,
+            browse_id3_ex(&id3, viewer.playlist, current_track->index + 1,
             viewer.num_tracks, NULL, 1) ? PV_ONPLAY_USB : PV_ONPLAY_UNCHANGED;
 }