added additionalProperties builder method
Merge pull request #175 from ctrimble/feature_with-additional-property

Builder Method for Additional Properties
[maven-release-plugin] prepare release jsonschema2pojo-0.4.2
[maven-release-plugin] prepare for next development iteration
[release] updating README.md for 0.4.2
Update changelog and contributors for 0.4.2
Make README.md update mandatory, fix 'next steps' for github