Improve readme

git-svn-id: https://plugins.svn.wordpress.org/dialogfeed/trunk@992435 b8457f37-d9ea-0310-8a92-e5e31aec5664
resolved reamde error

git-svn-id: https://plugins.svn.wordpress.org/dialogfeed/trunk@992436 b8457f37-d9ea-0310-8a92-e5e31aec5664