[swig] fix swig warnings for native bodies
[swig] fix swig warnings for native bodies

Fixes #15.

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