Add new 'callback' edit-menu types that call a function after the edit is done. Use this to display and edit Ki and Kd correctly (removing the scaling first and reapplying it after). Also use it to reset maximum stepwise acceleration rates, after updating mm/s^2 rates via menus. (Previously, changes did nothing to affect planner unless saved back to EEPROM, and the machine reset).
Add calls to updatePID() so that PID loop uses updated values whether set by gcode (it already did this), or by restoring defaults, or loading from EEPROM (it didn't do those last two). Similarly, update the maximum step/s^2 accel rates when the mm/s^2 values are changed - whether by menu edits, restore defaults, or EEPROM read.
Refactor the acceleration rate update logic, and the PID scaling logic, into new functions that can be called from wherever, including the callbacks.
Add menu items to allow the z jerk and e jerk to be viewed/edited in the Control->Motion menu, as per xy jerk.
Conflicts:
Marlin/language.h
A new variable was introduced to allow fan animation on the GLCD.
Add additional float to string conversion routine without sign
character. This is used for the coordinates visualisation on the GLCD.
[default off for now]
syntax: M600 X[pos] Y[pos] Z[relative lift] E[initial retract] L[later retract distance for removal]
if enabled, after a M600, the printer will retract by E, lift by Z, move to XY, retract even more filament.
Oh, and it will display "remove filament" and beep like crazy.
You are then supposed to insert a new filament (other color, e.g.) and click the display to continue.
After having the nozzle cleaned manually, aided by the disabled e-steppers.
After clicking, the printer will then go back the whole shebang, and continue printing with a fancy new color.
