Merge pull request #204 from hintjens/master

CZMQ doesn't build with libzmq 3.2.3 stable
Merge pull request #205 from hintjens/master

Minor cleanup of variable name
Merge pull request #206 from hintjens/master

Problem: zmsg_send() does nothing when given an empty message
Merge pull request #209 from hintjens/master

Fixed issue #208
Added note about tivotisation