[io, vview] fix missing math.inf in python2.7
[io, vview] fix missing math.inf in python2.7

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