[examples] OptimalControl.cpp: add missing header for numerics_set_verbose
[examples] OptimalControl.cpp: add missing header for numerics_set_verbose

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