Add Content Refresh Event to Pipeline Tutorial (#140)

* Added NotificationV2 and Group Events

NotificationV2 Events:
  notification-v2
  notification-v2-update
  notification-v2-delete
Group Events:
  group-joined
  group-left
  group-member-updated
  group-role-updated

* Fix some NotificationV2 things

* Added Content Refresh Event to Pipeline Tutorial

* Pull upstream

content/tutorials/websocket.markdown

@@ -346,6 +346,20 @@ A "`user-location`" event is sent when the user has changed instances.
 }
 ```
 
+
+#### content-refresh
+A "`content-refresh`" event is sent when the user adds or removes profile images etc.
+
+```json
+{
+    "type": "content-refresh",
+    "content": {
+        "contentType": ":contentRefreshContentTypeEnum", // One of: "gallery", "icon", "emoji", ???
+        "actionType": ":contentRefreshActionTypeEnum" // One of: "created", "deleted", ???
+    }
+}
+```
+
 ---
 
 ### Group Events