Introduce X-Frame-Origin header

Change-Id: Ia9b66297c68f819b26158c79fb2da6572c784898
diff --git a/lib/Kalamar.pm b/lib/Kalamar.pm
index 8efd919..a7c360b 100644
--- a/lib/Kalamar.pm
+++ b/lib/Kalamar.pm
@@ -112,6 +112,7 @@
     before_dispatch => sub {
       my $h = shift->res->headers;
       $h->header('X-Content-Type-Options' => 'nosniff');
+      $h->header('X-Frame-Options' => 'sameorigin');
       $h->header(
         'Access-Control-Allow-Methods' =>
           $h->header('Access-Control-Allow-Methods') // 'GET, POST, OPTIONS'