Bioinformatics Group, Department of Computer Science, University of Leipzig, Härtelstraße 16-18, Leipzig, 04107, Germany. lydia@bioinf.uni-leipzig.de.|Image and Signal Processing Group, Department of Computer Science, University of Leipzig, Augustusplatz 10, Leipzig, 04109, Germany.|Bioinformatics Group, Department of Computer Science, University of Leipzig, Härtelstraße 16-18, Leipzig, 04107, Germany.|Image and Signal Processing Group, Department of Computer Science, University of Leipzig, Augustusplatz 10, Leipzig, 04109, Germany.