Merge pull request #150 from miniway/master

Apply checkstyle and sample changes
Extend support for ZMQ monitors to inline with jzmq
Merge pull request #151 from ealgell/monitorpullreq

Extend support for ZMQ monitors to inline with jzmq
Added double checked locking for shared variable context. getContext() and createSocket() should now be thread safe.
Merge pull request #153 from devinrsmith/master

Added double checked locking for shared variable context in ZContext.
Add unbind method to org.zeromq.ZMQ.Socket
Merge pull request #156 from ealgell/master

Add unbind method to org.zeromq.ZMQ.Socket
Remove superfluous assignment
Change release version to 0.3.3-SNAPSHOT
Merge pull request #158 from trevorbernard/master

Remove superfluous assignment
[maven-release-plugin] prepare release v0.3.3
[maven-release-plugin] prepare for next development iteration
Update CHANGELOG.md
Fix issue where maven-release-plugin doesn't automatically tag in the correct format
[maven-release-plugin] prepare release v0.3.4
[maven-release-plugin] prepare for next development iteration
Update CHANGELOG.md
Capitalize constants
Use for each style
Issue #152 - Add unit test to test ZContext.close

Use for each style loop in destroy