compact representation of warning flags

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13704 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
get rid of deprecated operators (&) and (or)

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13705 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
extend warning 3 to other deprecated features: Latin1, (&) and (or)

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13706 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02