[swig] fix segfault test_serialization3:Python3, make binary_import/export use bytes.
[swig] fix segfault test_serialization3:Python3, make binary_import/export use bytes.

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