Minor README update

git-svn-id: https://plugins.svn.wordpress.org/bridgedd/trunk@894530 b8457f37-d9ea-0310-8a92-e5e31aec5664
Updated README for WP 3.9 compatibility

git-svn-id: https://plugins.svn.wordpress.org/bridgedd/trunk@894989 b8457f37-d9ea-0310-8a92-e5e31aec5664