Fix 3.x migration bug with zmq_sendmsg return value.
Merge pull request #40 from jtacoma/fix-sendmsg

Fix 3.x migration bug with zmq_sendmsg return value.
proxy device was added
test for proxy device was added
Merge pull request #44 from lorehov/master

Proxy device+tests added. Thanks to @lorehov.
Switch to .md and godocdown.
Moved docs into .godocdown.md.
Link to zguide examples.
Add reference to godocdown.
examples: Makefile -> go tool chain: removing Makefile, putting client and server in separate directories
Merge pull request #45 from psilva261/pullreq1

examples: Makefile -> go tool chain