Mdx 1.4.0

See full changelog
  • Add --force-output option to force generation of diff file (#118 @clecat)
  • Support OCaml 4.08.0 (#121 @xclerc)
  • README and documentation fixes (#122 #118 @andreypopp @clecat @samoht)
  • Use latest ocaml-migrate-parsetree interfaces (@avsm)