Merge pull request #331 from trevorbernard/master

Change artifactId back to jzmq
exposed plaintext gss sock opt
Merge pull request #334 from cbusbey/plain

exposed plaintext gss sock opt
Added method ZMQ.Socket.setProbeRouter(), issue #333
Merge pull request #336 from edgeofmagic/master

Added method ZMQ.Socket.setProbeRouter(), issue #333
Fix issue where release was failing because a circular reference
Update scm tags in pom.xml
Update release plugin
[maven-release-plugin] prepare release v3.1.0