Fix headers for WP 4+

git-svn-id: https://plugins.svn.wordpress.org/emailinvest/trunk@1045599 b8457f37-d9ea-0310-8a92-e5e31aec5664
Fix tests

git-svn-id: https://plugins.svn.wordpress.org/emailinvest/trunk@1045604 b8457f37-d9ea-0310-8a92-e5e31aec5664