Pass the room object into displayNotification

It needs it to do the view_room if the notification is clicked.

src/BasePlatform.js

@@ -63,7 +63,7 @@ export default class BasePlatform {
     requestNotificationPermission() : Promise<string> {
     }
 
-    displayNotification(title: string, msg: string, avatarUrl: string) {
+    displayNotification(title: string, msg: string, avatarUrl: string, room: Object) {
     }
 
     /**

src/Notifier.js

@@ -73,7 +73,7 @@ var Notifier = {
             ev.sender, 40, 40, 'crop'
         ) : null;
 
-        const notif = plaf.displayNotification(title, msg, avatarUrl);
+        const notif = plaf.displayNotification(title, msg, avatarUrl, room);
 
         // if displayNotification returns non-null,  the platform supports
         // clearing notifications later, so keep track of this.