deleting old files

git-svn-id: https://plugins.svn.wordpress.org/article-difficulty-level/trunk@845496 b8457f37-d9ea-0310-8a92-e5e31aec5664
updated to 3.8.1

git-svn-id: https://plugins.svn.wordpress.org/article-difficulty-level/trunk@845497 b8457f37-d9ea-0310-8a92-e5e31aec5664