Clean up POMs

Updated to new plugins and dependencies, removed old unused parts.
Implements #1217.
we should use maven-enforcer-plugin

 - [http://jira.codehaus.org/browse/MNG-4840](http://jira.codehaus.org/browse/MNG-4840?focusedCommentId=253900&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-253900)
 - http://maven.apache.org/enforcer/maven-enforcer-plugin/faq.html

(repost in the actual diffs)