Remove powered by link.

git-svn-id: https://plugins.svn.wordpress.org/newsletter-signup-form-by-comm100/trunk@872592 b8457f37-d9ea-0310-8a92-e5e31aec5664
Change version to 1.3

git-svn-id: https://plugins.svn.wordpress.org/newsletter-signup-form-by-comm100/trunk@872593 b8457f37-d9ea-0310-8a92-e5e31aec5664