Updating readme file to point to new stable tag

git-svn-id: http://plugins.svn.wordpress.org/active-directory-thumbnails/trunk@1290328 b8457f37-d9ea-0310-8a92-e5e31aec5664

BuddyPress avatar replacement now a user option in settings

git-svn-id: http://plugins.svn.wordpress.org/active-directory-thumbnails/trunk@1286062 b8457f37-d9ea-0310-8a92-e5e31aec5664