/// <summary>
        /// Initializes the singleton instance of this class and starts PCA
        /// computations if the library has been scanned already. Also causes
        /// TrackData to be written to the database if it is not current anymore.
        /// </summary>
        /// <param name="sc">
        /// The <see cref="NoNoiseClutterSourceContents"/> which is used as callback.
        /// </param>
        /// <param name="force_new">
        /// If this is true then a new instance will be initialized even if an
        /// old one already exists. Otherwise Init () might return an existing
        /// instance.
        /// </param>
        /// <returns>
        /// The singleton instance of <see cref="BansheeLibraryAnalyzer"/>
        /// </returns>
        public static BansheeLibraryAnalyzer Init (NoNoiseClutterSourceContents sc, bool force_new)
        {
            if (!force_new && bla != null)
                return bla;

            bla = new BansheeLibraryAnalyzer ();
            bla.sc = sc;

            Hyena.Log.Debug ("NoNoise/BLA - starting write track data thread");
            new Thread (new ThreadStart (bla.WriteTrackInfosToDB)).Start ();

            return bla;
        }
        /// <summary>
        /// Releases all resource used by the <see cref="Banshee.NoNoise.BansheeLibraryAnalyzer"/>
        /// object and removes all listeners which were previously added.
        /// </summary>
        /// <remarks>
        /// Call <see cref="Dispose"/> when you are finished using the
        /// <see cref="Banshee.NoNoise.BansheeLibraryAnalyzer"/>. The <see cref="Dispose"/> method leaves the
        /// <see cref="Banshee.NoNoise.BansheeLibraryAnalyzer"/> in an unusable state. After calling
        /// <see cref="Dispose"/>, you must release all references to the
        /// <see cref="Banshee.NoNoise.BansheeLibraryAnalyzer"/> so the garbage collector can reclaim the memory that
        /// the <see cref="Banshee.NoNoise.BansheeLibraryAnalyzer"/> was occupying.
        /// </remarks>
        public void Dispose ()
        {
            Hyena.Log.Debug ("NoNoise/BLA - Disposing library analyzer...");
            lock (scan_synch) {
                stop_scan = true;
            }

            ml.TracksAdded -= HandleTracksAdded;
            ml.TracksDeleted -= HandleTracksDeleted;
            sc = null;
            bla = null;
        }