adding note about CF7 incompatibility

git-svn-id: https://plugins.svn.wordpress.org/email-before-download/trunk@949039 b8457f37-d9ea-0310-8a92-e5e31aec5664
adding note about CF7 incompatibility

git-svn-id: https://plugins.svn.wordpress.org/email-before-download/trunk@949042 b8457f37-d9ea-0310-8a92-e5e31aec5664