Correct current sensor position, more robust loadcell offset compensa…

[ChrGri]

Hi @tjfenwick, my pedal is working now and I've made some changes to your code as described below:

• position values from 16bit to 32bit, as I had overflow before and pedal was suddenly jumping into min endstop.
• precompute pedal stiffness in setup to save runtime
• obtain current position from stepper. Before it was assumed that stepper finished movement within one cycle, resulting in wrong position. Can be easily verified by comparing the "Position_Next" and "currentPosition" after "currentPosition" is read.
• modified loadcell offset compensation to subtract the estimated offset.

[martinhoyer]

@ChrGri @tjfenwick You are heroes🏅 . I'd love to contribute but this is not exactly my forte. Is there a way I could at least buy you a beer/coffee? :)