Step size selection

[onsdagens]

Step size in the egui GUI is currently set by a slider. #95 bounded this slider to values that do not cause strange behaviour (0-u32::MAX).

We should probably remove this slider altogether and have this be an input field only, dragging to select a value between 0-u32::MAX makes little sense especially when the typical range you're actually looking for is more like 0-1000.