updated plugin tags

git-svn-id: https://plugins.svn.wordpress.org/retappd/trunk@966952 b8457f37-d9ea-0310-8a92-e5e31aec5664
adjusted installation instructions

git-svn-id: https://plugins.svn.wordpress.org/retappd/trunk@966956 b8457f37-d9ea-0310-8a92-e5e31aec5664