IOCaml 0.4.3

Remove dependancy on ocaml-zmq using a ctypes based binding.
Add new logo
iocaml-kernel depends on lwt (it doesn't really but the libs it exports do)
One attempt to get iocaml-0.3.1 building

on ocaml 4.00.1 (and passing travis) before I remove the package :)
Merge pull request #1996 from andrewray/iocaml-0.4.3

IOCaml 0.4.3