* mandos-monitor: Speedup: Use properties from D-Bus
                  GetAllClientsWithProperties() call.  Also use
                  super() properly - only use keyword arguments and
                  strip them off as "kwargs" is passed on.
  (MandosClientPropertyCache.__init__): Take new "properties"
                                        argument; use it to skip
                                        calling D-Bus GetAll() method.
                                        Call super().  Bind self._
  (MandosClientPropertyCache._property_changed): New helper function.
  (MandosClientPropertyCache.property_changed): Changed to take
                                                keyword arguments.
  (MandosClientPropertyCache.delete): Bug fix: Don't call
                                      super().__init__().
  (MandosClientWidget.__init__): Don't take *args.  Strip used keyword
                                 arguments before calling super().
  (MandosClientWidget.property_changed): Removed dead code.
  (MandosClientWidget.delete): Don't take *args.
  (MandosClientWidget.property_changed): Don't take "value" argument,
                                         since it is not used.
  (ConstrainedListBox.keypress): Take *args, **kwargs and pass them on
                                 to super().