[io] add verbose of multiplier in mechanics_io.py
[io] add verbose of multiplier in mechanics_io.py

bremond/siconos,fperignon/siconos,radarsat1/siconos,radarsat1/siconos,siconos/siconos,siconos/siconos,siconos/siconos,bremond/siconos,radarsat1/siconos,fperignon/siconos,fperignon/siconos,radarsat1/siconos,radarsat1/siconos,bremond/siconos,bremond/siconos,fperignon/siconos,bremond/siconos,fperignon/siconos,siconos/siconos