Tidy up code layout

git-svn-id: https://plugins.svn.wordpress.org/subscribe2/trunk@924522 b8457f37-d9ea-0310-8a92-e5e31aec5664
Better use of admin_url()

git-svn-id: https://plugins.svn.wordpress.org/subscribe2/trunk@924523 b8457f37-d9ea-0310-8a92-e5e31aec5664
Tidy up code

git-svn-id: https://plugins.svn.wordpress.org/subscribe2/trunk@924524 b8457f37-d9ea-0310-8a92-e5e31aec5664
ReadyGraph i18n changes to allow string translation

git-svn-id: https://plugins.svn.wordpress.org/subscribe2/trunk@924525 b8457f37-d9ea-0310-8a92-e5e31aec5664