Fixed readme typo.

git-svn-id: https://plugins.svn.wordpress.org/better-font-awesome/trunk@899890 b8457f37-d9ea-0310-8a92-e5e31aec5664
Fixed readme.

git-svn-id: https://plugins.svn.wordpress.org/better-font-awesome/trunk@899891 b8457f37-d9ea-0310-8a92-e5e31aec5664