Remove deprecated old Sock option API

The deprecated Sock option API has now been removed in favor of the new functional args API. Example:

sock := NewSock(Dealer)
defer sock.Destroy()
sock.SetOption(SockSetHeartbeatIvl(2000))

GoCZMQ Release 4.1.2

We are about to refactor the socket option API to use functional arguments to improve the overall user experience of the API. 4.1.0 is the last release to be compatible with the original socket option API.

GoCZMQ Release 4.0.2

This is the final release of GoCZMQ that will be backwards compatible with CZMQ 4.0. New releases, as well as the GoCZMQ master branch moving forward, will require CZMQ 4.2/

GoCZMQ Release 4.0.1

Merge pull request #220 from taotetek/master

Problem: sendframe signature changed

GoCZMQ Release 4.0

Compatible with >= CZMQ 4.0