export Bytearray.empty

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/safe-string@14612 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
export Bytearray.empty

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/safe-string@14613 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
convert some of the otherlibs to safe-string mode

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/safe-string@14614 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02