Simple POM improvements
- Maven version
  - update to the latest version (3.2.3)
  - use it in the javadoc links
- SCM developer connection
  - use it as site URL
  - use it for the maven-scm-publish-plugin
Define missing plugin versions
maven-versions-plugin:display-plugin-updates report:
[WARNING]   maven-clean-plugin .............. (from super-pom) 2.5
[WARNING]   maven-install-plugin ............ (from super-pom) 2.5.1
[WARNING]   maven-resources-plugin........... (from super-pom) 2.6
[WARNING]   maven-surefire-plugin ........... (from super-pom) 2.16
Update dependencies
maven-versions-plugin:display-dependency-updates:
[INFO]   org.apache.maven.reporting:maven-reporting-impl .... 2.1 -> 2.2
Merge pull request #8 from ferstl/pom-improvements

Some POM improvements