add OpenMesh_to_CGAL_Mesh and CGAL_Mesh_to_OpenMesh converters,
see OpenMesh_FilterAdapter.cxx for sample:

1) OpenMesh_to_CGAL_Mesh
2) CGAL triangulation
3) CGAL_Mesh_to_OpenMesh

but still problem during writing process (Ricardo, if you can look at this please...)