Updated dependency versions

Also updated to JDK 1.6 as the target.  This ensures proper "@Override"
handling on Eclipse.

Also used the current levels of Maven API.
Changed package name to have .mojo and fixed PMD

The messages are relocated to META-INF so it does not pollute the
namespace for dependencies.

Removed @Nullable annotation to remove the dependency on findbugs

Fixed @Override tag and META-INF reference