Fftdisplay and the display opcode (and Lissajous)

I never even thought to try this. That’s a happy accident. I guess we should probably discuss whether it would be better to create a new generic display widget that supports ‘spectrogram’, ‘spectroscope’ and ‘waveform’?

[edit] I’ve added a waveform display type to the fftdisplay.

But it doesn’t really make much sense in that widget. I propose a new signaldisplay widget which can be used to display signals as FFT or time-pressure graphs. fftwidget will still work as before. They will effectively be the same widget. When a user type fftdisplay Cabbage will actually create an signaldisplay widget. Or should I just call it display?