quick frontend (chat), primitivus(chat): properly clear occupants on resync:

occupants widgets were not cleared in Primitivus on resync while occupants dictionary was, resulting in nicknames sometimes apearing doubled in Primitivus MUC rooms.

A new occupantsClear method has been added in QuickChat, so it can be overriden by frontends to clear widgets or other representations of occupants.

fix 304

sat_frontends/quick_frontend/quick_chat.py

@@ -393,6 +393,13 @@ class QuickChat(quick_widgets.QuickWidget):
         self.sync = True
         self._resync_lock = False
 
+    def occupantsClear(self):
+        """Remove all occupants
+
+        Must be overridden by frontends to clear their own representations of occupants
+        """
+        self.occupants.clear()
+
     def resync(self):
         if self._resync_lock:
             return
@@ -408,7 +415,7 @@ class QuickChat(quick_widgets.QuickWidget):
             self.historyPrint(callback=self._resyncComplete, profile=self.profile)
             return
         if self.type == C.CHAT_GROUP:
-            self.occupants.clear()
+            self.occupantsClear()
             self.host.bridge.mucOccupantsGet(
                 unicode(self.target), self.profile, callback=self.updateOccupants,
                 errback=log.error)