'Cleans up after the node--removes terminals, graphicsItem, widget'

def close(self):

    self.disconnectAll()
    self.clearTerminals()
    item = self.graphicsItem()
    if (item.scene() is not None):
        item.scene().removeItem(item)
    self._graphicsItem = None
    w = self.ctrlWidget()
    if (w is not None):
        w.setParent(None)
    self.sigClosed.emit(self)
