Move nested class to top level, allowing more flexibility about reuse.

git-svn-id: https://svn.apache.org/repos/asf/creadur/rat/branches/gsoc@1549161 13f79535-47bb-0310-9956-ffa450edef68
Removed factory with only one method. More obvious to use the implementation directly, I think.

git-svn-id: https://svn.apache.org/repos/asf/creadur/rat/branches/gsoc@1549162 13f79535-47bb-0310-9956-ffa450edef68