Add ability to use custom waveforms in harmonic series of waveform editor besides sine waves

[m.samoljiuk]

In waveform editor, waveforms can be made out of sine waves that are arranged in harmonic series but I would like to be able to create custom waveforms using triangles or saws instead of sines. If that is impossible to do in waveform editor, then I would really like some sort of harmonics shaper that distorts/shapes harmonics(sine waves) into a custom waveform