Stepper Motor Support & minor fixes

[Robotmad]

Use more of the badge os hexpansion header handling code now it works.
Stepper Motor support:

1. new hexpansion type
2. 2 phase motor driver (not very fast though as can't be supported by hardware)
3. half and full step modes
4. endstop switch input on LS_E
5. software endstop (both ends) once physical endstop has been detected
6. "Stepper Test" mode with visualisation of position and control of position or speed.

[lincoltd7]

@copilot review this pr