Add Twitter link to the success message

git-svn-id: https://plugins.svn.wordpress.org/optimus/trunk@1043333 b8457f37-d9ea-0310-8a92-e5e31aec5664
Tested up to: WordPress 4.1

git-svn-id: https://plugins.svn.wordpress.org/optimus/trunk@1043334 b8457f37-d9ea-0310-8a92-e5e31aec5664