CHANGES:

• Support more than a single chunk extension for RFC7320 compliance (#618 by @djs55)
• Lwt-unix: add a ?backlog argument to the serve function (@samoht)
• Use the uri.2.0.0 interfaces for sexpression generation of types (@avsm)
• Switch to sexplib0 for a more lightweight s-expression library (@mseri)
• Minimum OCaml compiler version requirement is now 4.04.1 (@mseri)
• Add an example of using custom resolvers to the README (@mseri)