updating readme

git-svn-id: https://plugins.svn.wordpress.org/font-awesome-more-icons/trunk@758698 b8457f37-d9ea-0310-8a92-e5e31aec5664
updating plugin description

git-svn-id: https://plugins.svn.wordpress.org/font-awesome-more-icons/trunk@758699 b8457f37-d9ea-0310-8a92-e5e31aec5664