Releasing new version

TODO List:

• git checkout develop
• git flow release <version-number>
• Preparation:
  • Change version numbers in build.sbt and README.md
  • Add Release note on README.md
• git flow release finish <version-number>
• Assembles a jar, after moving jigg-models.jar into lib directory.
• Attach it to the release page.
• Deploy to maven by publishSigned and sonatypeRelease on sbt.