fix deprecation - Array.create

Array.create -> Array.make
fix bytes deprecation
local opam file

added base-bytes dependency
Merge branch 'fix_deprecation' of git://github.com/rgrinberg/ocaml-uri
opam: depend on camlp4 since we use sexplib.syntax
Drop support for OCaml 3.12.1, and now require OCaml 4.00.1+

This removes the toplevel libs hack from the _oasis file