Release version 4.0, major overhaul with some cool new features added

git-svn-id: https://plugins.svn.wordpress.org/yikes-inc-easy-mailchimp-extender/trunk@914175 b8457f37-d9ea-0310-8a92-e5e31aec5664
update readme.txt

git-svn-id: https://plugins.svn.wordpress.org/yikes-inc-easy-mailchimp-extender/trunk@914176 b8457f37-d9ea-0310-8a92-e5e31aec5664