Added Autotune and fixed pulsing

Completed adding autotune to lcd menu.  fixed pulsing in motors when
knob is turned.  Added initialization of extruder on/off pin.   removed
'ABS' from menu text.  Made winder work with RPM and calibration factor.
Adjusted max rpms

Updated max step freq to 50,000.  Adjusted max extruder rpm to 50, but
still seems to be limited to 25rpm.  Adjusted max puller mm/s to 15, the
max limit based on a 100:1 motor and 50,000 pulses per sec.