Upgrade Maven dependencies

[Bananeweizen]

• pin versions of jxr and surefire-report plugin, they were undefined up to now
• upgrade all maven plugin versions except Tycho (that should be done separately)
• add the versions-plugin to make the search for updates itself reproducible
• disallow any kind of non-stable version when looking for maven plugin updates via a property of the versions plugin
• upgrade the external checkstyle application version to most recent release
• Improve configuration of maven-dependency plugin, because the new version recognizes more dependency problems than before. Also have some more dependencies in test scope only, because they are used in tests only.