fix thresholds to allow None threshold and to use previously defined motif.py functions; also converted thresholds.py::output_motifs to motif.py::get_put_motifs
fix thresholds to allow None threshold and to use previously defined motif.py functions; also converted thresholds.py::output_motifs to motif.py::get_put_motifs

j-andrews7/VENUSAR,j-andrews7/VAMPIRE