deleting old files


git-svn-id: https://plugins.svn.wordpress.org/article-difficulty-level/trunk@853357 b8457f37-d9ea-0310-8a92-e5e31aec5664
version 2.2 added for article difficulty level

git-svn-id: https://plugins.svn.wordpress.org/article-difficulty-level/trunk@853358 b8457f37-d9ea-0310-8a92-e5e31aec5664