Fix header warning

git-svn-id: https://plugins.svn.wordpress.org/smsify/trunk@961651 b8457f37-d9ea-0310-8a92-e5e31aec5664
Fix icon URL path

git-svn-id: https://plugins.svn.wordpress.org/smsify/trunk@961652 b8457f37-d9ea-0310-8a92-e5e31aec5664