[MEAR-180]
 - Checking the list of modules if we have 
   duplicate artifacts and produce a warnging
   optionally fail the build to keep backward
   compatibility.


git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1636439 13f79535-47bb-0310-9956-ffa450edef68
[MJAR-189] Upgrade plexus-archiver dependency to v2.8.1

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1636442 13f79535-47bb-0310-9956-ffa450edef68