Trivial casts in setsockopt_num()/getsockopt_num() are okay.
Trivial casts in setsockopt_num()/getsockopt_num() are okay.

jedisct1/rust-zmq,pfernie/rust-zmq,pblasucci/rust-zmq,petehayes102/rust-zmq,tempbottle/rust-zmq,alexkamp/rust-zmq,dginev/rust-zmq,erickt/rust-zmq