add sag parameters to the clipping in both pre and power stages
re-visit plate modeling, simplified power law to a scale, while not
correct the results are close to those observed in simulatio and it
helps both performance and fitting / maintaining the model.
removed capacitance from model to simplify fitting
update ui for new dsp
no longer providing distortion controls as they aren't easy to
separate from the touch sensitivity
update dsp models
update ui for new dsp