Merge pull request #220 from hintjens/master

Gossip-based discovery now works
Merge pull request #221 from hintjens/master

Further work on Zyre gossip discovery
Merge pull request #224 from hintjens/master

Fixes for Windows and HELLO sequencing
Merge pull request #225 from hintjens/master

Fix dangling use of CZMQ_EXPORT (needed zproto upatch)
Merge pull request #226 from hintjens/master

Show more information on zyre_peer_connect failure
Fix formats passed in ztester tools

Caused format specification errors under clang on MacOS:
argument has type 'int64_t' (aka 'long long') [-Werror,-Wformat]
Merge pull request #227 from twhittock/format-fix

Fix formats passed in ztester tools
Problem: zyre_peer_connect using bad endpoint

Due to confusion in design, node was sometimes announcing internal endpoint
like "tcp://*:12345" for public use in HELLO, causing failure in
zyre_peer_connect ().

Solution: remove confusing API options, require that zyre_set_endpoint
provide an endpoint valid both for bind and for connect, and announce the
correct endpoint in HELLO messages.