Handle update events on bokeh server.

def update(self):
        """
        Handle update events on bokeh server.
        """
        if not self._queue:
            return

        dim, widget_type, attr, old, new = self._queue[-1]
        self._queue = []
        dim_label = dim.pprint_label

        label, widget = self.widgets[dim_label]
        if widget_type == 'label':
            if isinstance(label, AutocompleteInput):
                value = [new]
                widget.value = value
            else:
                widget.value = float(new)
        elif label:
            lookups = self.lookups.get(dim_label)
            if not self.editable:
                if lookups:
                    new = lookups[widget.value][1]
                label.text = '<b>%s</b>' % dim.pprint_value_string(new)
            elif isinstance(label, AutocompleteInput):
                text = lookups[new][1]
                label.value = text
            else:
                label.value = dim.pprint_value(new)

        key = []
        for dim, (label, widget) in self.widgets.items():
            lookups = self.lookups.get(dim)
            if label and lookups:
                val = lookups[widget.value][0]
            else:
                val = widget.value
            key.append(val)
        key = wrap_tuple_streams(tuple(key), self.plot.dimensions,
                                 self.plot.streams)
        self.plot.update(key)
        self._active = False