Make sure that message delegates are getting the room object directly rather than requiring the assumption that currentRoom is declared somewhere higher up.
This MR deals with only sending threaded messages. Showing threads will turn up in a follow up. This allows you to start a new thread by clicking reply in thread to a normal message.
You can also do a threaded reply to a threaded message in the main timeline at the moment because those messages aren't shown in a separate thread timeline yet but will be in future.
