removing php warnings and adding screenshot to readme.txt file again

git-svn-id: https://plugins.svn.wordpress.org/buddypress-foaf/trunk@852190 b8457f37-d9ea-0310-8a92-e5e31aec5664
minor changes for readme file

git-svn-id: https://plugins.svn.wordpress.org/buddypress-foaf/trunk@852191 b8457f37-d9ea-0310-8a92-e5e31aec5664
minor changes for readme file

git-svn-id: https://plugins.svn.wordpress.org/buddypress-foaf/trunk@852193 b8457f37-d9ea-0310-8a92-e5e31aec5664