Animate dots at the end of the splash screen message.

def animate_ellipsis(self):
        """Animate dots at the end of the splash screen message."""
        ellipsis = self.ellipsis.pop(0)
        text = ' '*len(ellipsis) + self.splash_text + ellipsis
        self.ellipsis.append(ellipsis)
        self._show_message(text)