correction to readme

git-svn-id: https://plugins.svn.wordpress.org/share-me/trunk@1033207 b8457f37-d9ea-0310-8a92-e5e31aec5664
correction to readme

git-svn-id: https://plugins.svn.wordpress.org/share-me/trunk@1033210 b8457f37-d9ea-0310-8a92-e5e31aec5664