ZeroMQ 3.x: Conditionally support ZMQ_SWAP socket option.
ZeroMQ 3.x: Adjust socket option data types
ZeroMQ 3.x: HWM -> SNDHWM / RCVHWM
ZeroMQ 3.x: ZMQ_NOBLOCK -> ZMQ_DONTWAIT
ZeroMQ 3.x: Conditionally use new API functions
ZeroMQ 3.x: Remove ZMQ_RECOVERY_IVL_MSEC; adjust ZMQ_RECOVERY_IVL to take a (possibly non-integer) number and convert internally to milliseconds
fix version checks
Replace zmq_init.
Fix order of arguments in zmq_send_msg and zmq_recv_msg.
Merge branch 'zeromq3'