[FIXED]A different way to do bore/stroke

[Frankschtaldt]

I get the feeling that the current system of having a volume slider as well as bore and stroke sliders seems to cause some issues. It seems to be quite a common place for bugs to show up.
I have two suggestions to simplify it a bit.
1) do away with the volume slider and just have bore and stroke
2) do away with bore and stroke sliders and have a volume slider with a new over/under square slider.