added link for contact/support for setup.

git-svn-id: https://plugins.svn.wordpress.org/authorizenet-payment-gateway-for-woocommerce/trunk@745538 b8457f37-d9ea-0310-8a92-e5e31aec5664
stable tag update

git-svn-id: https://plugins.svn.wordpress.org/authorizenet-payment-gateway-for-woocommerce/trunk@745539 b8457f37-d9ea-0310-8a92-e5e31aec5664
screenshot removed

git-svn-id: https://plugins.svn.wordpress.org/authorizenet-payment-gateway-for-woocommerce/trunk@745540 b8457f37-d9ea-0310-8a92-e5e31aec5664