minor optimizations

	modified:   lib/POEx/ZMQ.pm
	modified:   lib/POEx/ZMQ/FFI/Role/ErrorChecking.pm
	modified:   lib/POEx/ZMQ/FFI/Socket.pm
	modified:   t/ffi/socket.t
micro-optimize FFI::Socket->send(_multipart)

	modified:   lib/POEx/ZMQ/FFI/Socket.pm