Visualisation demos: Automatic on idle/playback menu option

[skxr]

So well there is this oscilloscope demonstration and spectrum viewer demonstration, even a spectrogram demonstration! Would it be possible to make them options in playback menu? Going to demonstrations every time is not great option.

I know that in "portable" situations it's senseless but if Rockbox team decided to make these demonstration plugins, which can be sometimes useful, then it's good to make step further.