updated readme

git-svn-id: https://plugins.svn.wordpress.org/ag-custom-admin/trunk@967398 b8457f37-d9ea-0310-8a92-e5e31aec5664
updated readme

git-svn-id: https://plugins.svn.wordpress.org/ag-custom-admin/trunk@967400 b8457f37-d9ea-0310-8a92-e5e31aec5664