[io]  fix multiple identical times of births by using set()
[io]  fix multiple identical times of births by using set()

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