The I2C LCD status indicators now indicate when the hotends or bed are
turned on at all (rather than just when they are in their heating phase)

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

The new version of the library means that PANELOLU no longer needs to be
defined in LiquidTWI.h (the library file can be used as is) and the new
version of the library also enables the buzzer on the Panucatt VIKI
panel.

This change also handles the case where the pause/stop/restart button on
the VIKI is not used. Make LCD I2C buzz sound the same as the normal
buzz (300ms is too long for quick feedback).

Refactor configuration to try to make items clearer (what defines a
panel vs what is user changeable).

This includes refactoring the buttons code to remove a large amount of
non-pin dependent duplication from pins.h.

Removed incorrect LiquidCrystal_I2C Library

Fix to a bug that I just introduced - sorry. Forgot about offset of string length.

Use all available characters in narrow LCDs < 20 characters.

Fix to a minor bug with hardcoded LCD_WIDTH that draws edited values outside of the 16 characters width LCDs.