Include check for 'later' cookie within start method of tour (#27)

Thanks @rroppolo!

app/views/application/_abraham.html.erb

@@ -51,8 +51,14 @@
   });
   <% end %>
 
+  tour.start = function (start) {
+    return function () {
       // Don't start the tour if the user dismissed it once this session
       if (!Cookies.get('<%= abraham_cookie_prefix %>-<%= tour_name %>', {domain: '<%= abraham_domain %>'})) {
-    tour.start();
+        start();
       }
+    }
+  }(tour.start)
+
+  tour.start()
 </script>