Fix race condition on shutdown
Backported LIBZMQ-39 fix
Revert "zmq: add TIPC transport tests"

This reverts commit d0aa05fac49ef3640a99c67d323bb3d062f6c355.
Revert "zmq: add support for TIPC transport"

This reverts commit dbc42ee9af098183714845a75139997dcc34c7a0.
Merge pull request #112 from hintjens/master

Backported fix for libzmq-39