readme.txt updated

git-svn-id: https://plugins.svn.wordpress.org/facebook-page-promoter-lightbox/trunk@866223 b8457f37-d9ea-0310-8a92-e5e31aec5664
fixed tags

git-svn-id: https://plugins.svn.wordpress.org/facebook-page-promoter-lightbox/trunk@866248 b8457f37-d9ea-0310-8a92-e5e31aec5664