Better documentation of meta format conversion.

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13714 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
Tabify.

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13715 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
Adding a test directory for the Format module.

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13716 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02