Validate readme

git-svn-id: https://plugins.svn.wordpress.org/newsme/trunk@933060 b8457f37-d9ea-0310-8a92-e5e31aec5664
Fix readme case study url

git-svn-id: https://plugins.svn.wordpress.org/newsme/trunk@933062 b8457f37-d9ea-0310-8a92-e5e31aec5664
Heading in box case study

git-svn-id: https://plugins.svn.wordpress.org/newsme/trunk@933064 b8457f37-d9ea-0310-8a92-e5e31aec5664