Version setup.ml to preserve the OCAML_TOPLEVEL_PATH trick.

Setting the path according to OCAML_TOPLEVEL_PATH will be present in
the next version of oasis but until then, it is necessary to add it by
hand.  setup.ml may be erased by distclean.
Process error messages for both OCaml 3.12 and 4.0
replace JaneSt logos