update readme

git-svn-id: https://plugins.svn.wordpress.org/visual-website-editor/trunk@930853 b8457f37-d9ea-0310-8a92-e5e31aec5664
update readme

git-svn-id: https://plugins.svn.wordpress.org/visual-website-editor/trunk@930855 b8457f37-d9ea-0310-8a92-e5e31aec5664