stabilized the hysteresis calibration

I removed the center re-calculation from the bounding measurement. This
allows the upper and lower hysteresis to be different relative to the
center.
Merge branch 'master' of https://github.com/Technocopia/ServoStock

Conflicts:
	firmware/MplabX_Projects/ServoPrinterController.X/dist/default/production/ServoPrinterController.X.production.elf
	firmware/MplabX_Projects/ServoPrinterController.X/dist/default/production/ServoPrinterController.X.production.hex
	firmware/MplabX_Projects/ServoPrinterController.X/dist/default/production/ServoPrinterController.X.production.map
	firmware/src/kinematics/CartesianController.c
	firmware/src/motion/servoCalibration.c