Updated Screenshots.

git-svn-id: https://plugins.svn.wordpress.org/email-blaster-newsletter-signup-form/trunk@963678 b8457f37-d9ea-0310-8a92-e5e31aec5664
updated readme.txt

git-svn-id: https://plugins.svn.wordpress.org/email-blaster-newsletter-signup-form/trunk@963683 b8457f37-d9ea-0310-8a92-e5e31aec5664