[mechanics] import native classes at collision level
[mechanics] import native classes at collision level

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