maintain the global notification timeline set.

* track notifTimelineSet on MatrixClient
* stop Rooms from tracking notifTimelineSet as they don't need to
* Implement client.paginateNotifTimelineSet
* make Events store their pushActions properly
* insert live notifs directly into the notifTimelineSet in /sync, ordering by origin_server_ts.

lib/models/event.js

@@ -76,6 +76,7 @@ module.exports.MatrixEvent = function MatrixEvent(event, clearEvent) {
     this.forwardLooking = true;
 
     this._clearEvent = clearEvent || {};
+    this._pushActions = null;
 };
 
 module.exports.MatrixEvent.prototype = {
@@ -294,6 +295,24 @@ module.exports.MatrixEvent.prototype = {
     isRedacted: function() {
         return Boolean(this.getUnsigned().redacted_because);
     },
+
+    /**
+     * Get the push actions, if known, for this event
+     *
+     * @return {?Object} push actions
+     */
+     getPushActions: function() {
+        return this._pushActions;
+     },
+
+    /**
+     * Set the push actions for this event.
+     *
+     * @param {Object} pushActions push actions
+     */
+     setPushActions: function(pushActions) {
+        this._pushActions = pushActions;
+     },
 };