added secondary class to buttons

git-svn-id: https://plugins.svn.wordpress.org/contact-form-7-html-editor/trunk@881492 b8457f37-d9ea-0310-8a92-e5e31aec5664
added secondary class to buttons

git-svn-id: https://plugins.svn.wordpress.org/contact-form-7-html-editor/trunk@881494 b8457f37-d9ea-0310-8a92-e5e31aec5664