This release contains important API changes that may break existing
code.
1. Incompatible change: `Socket.send` series methods are splitted
to `Socket.send` and `Socket.sendMore` and have more overloads for
common message types like string or empty
2. Remove PollItem duplicate API (#11)
3. Fix compiler warning (#10) and compile failure (#12)
4. Add RTReq example from ZMQ Guide Chapter 3