Add missing license headers, and one exclusion for RAT.

git-svn-id: https://svn.apache.org/repos/asf/maven/enforcer/trunk@1585357 13f79535-47bb-0310-9956-ffa450edef68
updated parent pom

git-svn-id: https://svn.apache.org/repos/asf/maven/enforcer/trunk@1586889 13f79535-47bb-0310-9956-ffa450edef68
simplified configuration: values are either inherited or default values

git-svn-id: https://svn.apache.org/repos/asf/maven/enforcer/trunk@1586948 13f79535-47bb-0310-9956-ffa450edef68
avoid copy/paste: use property

git-svn-id: https://svn.apache.org/repos/asf/maven/enforcer/trunk@1586949 13f79535-47bb-0310-9956-ffa450edef68
- Small code clean ups.
- Fixed typos.
- Added JavaDoc


git-svn-id: https://svn.apache.org/repos/asf/maven/enforcer/trunk@1588746 13f79535-47bb-0310-9956-ffa450edef68