Added PublishWorkFlowInterface
Implemented PublishWorkflowChecker on ContentAwareFactory

- Only checks child nodes
- Added test
Update .travis.yml
Merge pull request #61 from KingCrunch/travis-update-symfony-2.3

Update .travis.yml
make composer happy
Added CHANGELOG
Merge pull request #53 from dantleech/publish-workflow

Added PublishWorkFlowInterface