Switch to semantic versioning
Update dependencies
Add Dennis Oelkers to contributors
Remove GitHub downloads-maven-plugin
Change Maven site deployment to GitHub with Maven plugin

The current version of the Maven site (and Javadoc) will be deployed to a
subdirectory denoting the version of the project.
Define Maven 3.0.0 as prerequisite
Clean up and update Maven plugins
Add ciManagement section in POM
Update README file