liveobjects: add object modes

Author: mschristensen

content/channels/options/index.textile

@@ -415,6 +415,8 @@ The channel mode flags available are:
 | PUBLISH | Can publish messages to the channel. |
 | PRESENCE_SUBSCRIBE | Can subscribe to receive presence events on the channel. |
 | PRESENCE | Can register presence on the channel. |
+| OBJECT_PUBLISH | Can update objects on the channel. |
+| OBJECT_SUBSCRIBE | Can subscribe to receive updates to objects on the channel. |
 
 The following is an example of setting channel mode flags: