replace extruder_multiply with extruder_multiplier
like feedrate_multiplier or volumetric_multiplier

- Use `setTargetedHotend` in `M200`, as with other commands that use
`T` for the extruder
- Synthesize the "invalid extruder" message, obviating several long
strings

To avoid double definitions.
I prefer to read N for Number not for Nozzle.

Was omitted when T0 is a MAX6675.

My PID_INTEGRAL_DRIVE_MAX was at 96, which was insufficient for my bed
to reach its intended temperature. The head requires a low maximum power since
I run on 24 volts and it has a somewhat low thermal mass.

to have it ready to display errors during (temperature)-setup.

- The command parser now displays “unknown command” in more cases.
Known commands must be added to the `switch` inside `process_commands`
to suppress the error.

And call _temp_error() directly for ERR_MAXTEMP_BED to avoid the only one time use of bed_max_temp_error().

Includes #2156.

to avoid stack overflow when called from interrupt.

Some clean up for calls of disable_all_heaters().
'disable_all_heaters()' is called in kill() and again when 'killed' is already set inside _temp_error().

- Affects code size when automatic bed leveling is enabled

!(~(ab)&0x3) and ab == 0x3 are equal

to warrant watching is set or reset.

Make setTargetBed() in _lcd_preheat() dependant of TEMP_SENSOR_BED.
Use disable_all_heaters() in lcd_cooldown() and abort_on_endstop_hit.

in temperature.cpp

Makes the output on the LCD adjustable.

instead of stop(). We really want to require a reset and no chance to set a new temperature.

Updated all the example Configuration.h files for the new display type.

Added the link to the github information about the
ELB_FULL_GRAPHIC_CONTROLLER

No way to fit Marlin into 32K.

Fixed a couple defines that were not changed or commented out.