ZMQ_LINGER 0 seems to cause hangs, although it ought not.

	new file:   MANIFEST
	new file:   MANIFEST.SKIP
	modified:   lib/POEx/ZMQ3/Replier.pm
	modified:   lib/POEx/ZMQ3/Requestor.pm
	modified:   lib/POEx/ZMQ3/Role/Emitter.pm
	modified:   lib/POEx/ZMQ3/Role/Endpoints.pm
	modified:   lib/POEx/ZMQ3/Role/Sockets.pm
	deleted:    scratchpad