Finish attributes on module/recursive modules in structures.

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/extension_points@13354 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
Switch Pstr_modtype argument to a record type.

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/extension_points@13355 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02