Integrated support for automated Javadoc publication

Javadocs are at our github project site
http://wikidata.github.io/Wikidata-Toolkit/
They can be updated by running:

 mvn clean javadoc:aggregate scm-publish:publish-scm
[maven-release-plugin] prepare release v0.2.0
Merge branch 'master' of https://github.com/Wikidata/Wikidata-Toolkit into create-parser-of-constraints