Simplify maven configuration
Simplify maven configuration

Use maven properties rather than a specific plugin version
and additionnal settings in the parent pom

galmeida/raven-java,littleyang/raven-java,reki2000/raven-java6,buckett/raven-java,buckett/raven-java,galmeida/raven-java,littleyang/raven-java,reki2000/raven-java6