updated form.php

git-svn-id: https://plugins.svn.wordpress.org/easy-mailchimp-opt-in/trunk@985373 b8457f37-d9ea-0310-8a92-e5e31aec5664
version 1.3 mailchimp-optin.php

git-svn-id: https://plugins.svn.wordpress.org/easy-mailchimp-opt-in/trunk@985378 b8457f37-d9ea-0310-8a92-e5e31aec5664