Handle user events Redis not working in tutorial

Also does some basic restyling

Fixes #1586

static/js/tour.js

@@ -286,6 +286,10 @@ angular.module("angular-tour", [])
         checker.$source.onmessage = function(e) {
           checker.$message = JSON.parse(e.data);
         };
+        checker.$source.onerror = function(e) {
+          bootbox.alert('Could not read user events from server due to a Redis issue. ' +
+                        ' Please contact support.')
+        };
       };
 
       checker.$teardown = function() {