restore accidentally-removed toString()

Author: Josh

site/themes/s2b_hugo_theme/assets/js/cal/helpers.js

@@ -97,7 +97,7 @@
           output: 'xml'
         });
 
-        return googleCalUrl;
+        return googleCalUrl.toString();
     };
 
     $.fn.compareTimes = function ( event1, event2 ) {