primitivus (chat): added :topic (and :subject and :title aliases) to change subject with a dialog (/!\ urwid SàText need to be updated)

frontends/src/quick_frontend/quick_chat.py

@@ -423,9 +423,17 @@ class QuickChat(quick_widgets.QuickWidget):
 
     def setSubject(self, subject):
         """Set title for a group chat"""
-        self.subject = subject
         if self.type != C.CHAT_GROUP:
             raise exceptions.InternalError("trying to set subject for a non group chat window")
+        self.subject = subject
+
+    def changeSubject(self, new_subject):
+        """Change the subject of the room
+
+        This change the subject on the room itself (i.e. via XMPP),
+        while setSubject change the subject of this widget
+        """
+        self.host.bridge.mucSubject(unicode(self.target), new_subject, self.profile)
 
     def addGamePanel(self, widget):
         """Insert a game panel to this Chat dialog.