Sexp support for most types

• Add some module type equalities in Cohttp_lwt_unix so that
  Cohttp_lwt_unix.Server.Request.IO.ic can be equivalen to Lwt_io.input_channel.
• Add sexp converters to most Cohttp types (#83).
• Improve Travis tests to cover more upstream users of Cohttp.
• Refactor build flags to let the portable Lwt-core be built independently of Lwt.unix.

Cookie improvements, API consistency and better header parsing

• Remove Cohttp_mirage libraries, which have now moved to mirage/mirage-http-* on GitHub.
• Add an "HTTP only" Cookie attribute (#69).
• Fix parsing of cookies with = in the values (#71).
• Add Max-age support for cookies (#70).
• Make the Response record fields mutable to match the Request (#67).
• Fix compilation with Async 109.58.00 (#77).
• Make Header handling case-insensitive (by forcing lowercase) (#75).
• Remove the >> operator as it was unused and had incorrect precedence (#79).

Better Server-Side Event support, complete HTTP codes and install a server binary

• Install a cohttp-server binary that serves local directory contents via a web server (#54).
• Add a flush function to the IO module type and implement in Lwt/Async/Mirage.
• Add option flush support in the Async and Lwt responders (#52).
• Autogenerate HTTP codes from @citricsquid's JSON representation of the HTTP RFCs.
• Always set TCP_NODELAY for Lwt/Unix server sockets for low-latency responses (#58).
• Added a Server-Side Events test-case from the HTML5 Doctor. See lib_test/README.md.
• Async.Server response now takes an optional body rather than a mandatory body option (#62).
• Regenerate build system using OASIS 0.4.0.

Mirage 1.0 support and Lwt-core

• The cohttp.lwt-core is now installed as an OS-independent Lwt library.
• Add support for Mirage 1.0, via cohttp.mirage-unix and cohttp.mirage-xen.
• Add a new Cohttp.Connection module to manage server's connections identifiers.
• Share the same configuration type for the different server implementations.
• Add Accept_types module to the Cohttp pack.

Polishing the interfaces to a fine shine

• Improve documentation for Cohttp.Header.
• Expose Fieldslib setters and getters for most of the Cohttp types (#38).
• Cohttp.Set_cookie.t is no longer an abstract type to make it easier to update (#38).
• [Lwt] ignore SIGPIPE unconditionally if using the Lwt/Unix module (#37).
• Rename Cookie creation parameters for consistency (interface breaking, see #44).
• Fix transfer-length detection (regression from 0.9.11 in #42).
• Add Merin editor file (#41).

Mini features: HTTP 1.0 improved, OPTIONS and Travis

• Request module: When sending a request, add the port information in the host header field if available.
• Request module: When parsing a request, add scheme, host and port information in the uri.
• TCP server: When creating the socket for the server, do not force PF_INET6 but take the sockaddr value.
• Add HTTP OPTIONS method.
• Use getaddrinfo instead of gethostbyname for DNS resolution.
• Async: improve HTTP/1.0 support (#35).
• Build with debug symbols, binary annotations by default.
• Add Travis CI test scripts.