Use FastIO for spindle, probe test, and case light

"Keepalive" is now "Busy protocol"

Patch M23 to work around Simplify3D bug

Fixes #7250

Addressing #7227

Add PROBE_MANUALLY support to G33

UTF-8 mapper for Czech

Add configurable action command to send when printer is killed

DISABLE_[XYZ] compatibility check

DISABLE_[XYZ] is incompatible with HOME_AFTER_DEACTIVATE and Z_SAFE_HOMING

Sends pre-defined string as action command when printer is kill.

Fix for issues #6997 and #7152

Probing with the effector in the printing area, but an eccentric probe (e.g. allen key) outside it but still touching the bed gives meaninfull information for calibration. Since calibration is most accurate when probing as close to the towers as possible the testing was way to restrictive hence this fix.

Update Marlin+git helper scripts

Make all EEPROM optimization options available

M48 needs a real probe

Use lcd_bootscreen for both

Printrboard RevF cleanup

-Update Arduino IDE extension descriptions
-Set default motor currents if not defined in Configuration_adv.h
-Support for MINIPANEL LCD
-Support for choosing internal or panel SD

LCD for Melzi support

Expose DISABLE_M503 option as a test option

UBL radar map corrections

Add configuration for Infitary M508 (i3 clone)

Based on Infitary's own firmware settings.