Toralf Wittner      original implementation
David Himmelstrup   added send'
Nicolas Trangez     added support for zmq_device and "queue" test app
Ville Tirronen      added support for ZMG_SNDMORE
Jeremy Fitzhardinge integrated with GHC's I/O manager
Bryan O'Sullivan    added resource wrappers, socket finalizer
Ben Lever           fixed and tweaked some of the test examples