Wishlist: randomize detuning for the played note

[suedwestlicht]

To humanize playback even more it would be cool if there was a "randomized detuning" parm. This value will be determined at the start of playing the sample and not change during this note-on event. So we just have a randomized but fixed detuning per note, no further modulation.

The parm determines how much the sound will be detuned (+-) at most.