rework code after MNG-5720 discussion

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1637568 13f79535-47bb-0310-9956-ffa450edef68
[MPIR-306] Upgrade to maven-plugins version 25 to 26
 - Fixed several checkstyle reported errors.


git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1637570 13f79535-47bb-0310-9956-ffa450edef68
- Removed unused code.

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1637571 13f79535-47bb-0310-9956-ffa450edef68
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)