Return event_id from room methods that send messages

The "event_id" returned by the HS is returned directly, instead of
a lone table with a single "event_id" member, for the following methods:

  room:send_text()
  room:send_emote()
  room:send_notice()

matrix/client.lua

@@ -144,15 +144,18 @@ function Room:_log(fmt, ...)
 end
 
 function Room:send_text(text)
-   return self.client._api:send_message(self.room_id, text)
+   -- XXX: How does error handling work here?
+   return self.client._api:send_message(self.room_id, text).event_id
 end
 
 function Room:send_emote(text)
-   return self.client._api:send_emote(self.room_id, text)
+   -- XXX: How does error handling work here?
+   return self.client._api:send_emote(self.room_id, text).event_id
 end
 
 function Room:send_notice(text)
-   return self.client._api:send_notice(self.room_id, text)
+   -- XXX: How does error handling work here?
+   return self.client._api:send_notice(self.room_id, text).event_id
 end
 
 function Room:invite_user(user_id)