RAT-177 Converted arrays to list

* Converted array elements into an unmodifiable collection.
* Using lists instead of arrays to ease copy/addAll().



git-svn-id: https://svn.apache.org/repos/asf/creadur/rat/trunk@1625380 13f79535-47bb-0310-9956-ffa450edef68
Adding idea files to gitignore.


git-svn-id: https://svn.apache.org/repos/asf/creadur/rat/trunk@1625381 13f79535-47bb-0310-9956-ffa450edef68