Add ZMQ::Poller
Add documentation to ZMQ::Poller
Check that ZMQ::Poller is loaded.
ZMQ::call('zmq_poll') instead zmq_poll directly

This commit calls zmq_poll with ZMQ::call instead of directly through a
backend. This changes the return value from zmq_poll somehow. The new
code is to fix the return value from zmq_poll.
Change 201_poller.t to choose the right send/recv
Merge branch 'master' of git://github.com/pstuifzand/p5-ZMQ into topic/zmq-poller
Merge branch 'master' into topic/zmq-poller
Tweak docs
version++; this be 1.04
version++; this be ZMQ-LibZMQ3 1.03
version++; this be ZMQ-1.03
version++; This be ZMQ-CZMQ-1.03