Shipping errors shown only to site admin, and changed internally used debug constant name

git-svn-id: https://plugins.svn.wordpress.org/woocommerce-smart-send-australian-shipping/trunk@1020816 b8457f37-d9ea-0310-8a92-e5e31aec5664
Shipping errors shown only to site admin, and changed internally used debug constant name

git-svn-id: https://plugins.svn.wordpress.org/woocommerce-smart-send-australian-shipping/trunk@1020817 b8457f37-d9ea-0310-8a92-e5e31aec5664