Support for quoted strings.

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/extension_points@13450 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
Document changes to the Typedtree.

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/extension_points@13451 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
Simplify.

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/extension_points@13452 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02