Update dependencies.

Bring various dependencies up to more recent versions.
(ie site plugin, plexus-utils, maven-plugin-testing-harness, animal
sniffer, mojo signature).
Remove some unnecessary overrides in pom (maven plugin annotatinos &
modello-maven-plugin).
Now java 6 - add more support

Add missing overrides
Removed unused imports
Add list/array list types (ie ReportPlugin & String)