Add SDEXTRASLOW which runs the SD card at SPI_QUARTER_SPEED. Quarter speed is needed for RIGIDBOT_PANEL

With the introduction of the #if ENABLED(…)

reads better than

* Updates the auto bed leveling comments ONLY.
* Renames "Z probe" word usage in //comments and #errors properly.

Currently we use the probe exclusively as a device to find the build platform(bed).
For the currently supported setups this means, we use it as a additional min-endstop.
A triggered when not deployed probe disturbs the homing process for max-endstops.

Rename ENDSTOPPULLUP_ZPROBE to ENDSTOPPULLUP_ZMIN_PROBE
Rename Z_PROBE_ENDSTOP_INVERTING to Z_MIN_PROBE_ENDSTOP_INVERTING
Rename Z_PROBE_ENDSTOP to Z_MIN_PROBE_ENDSTOP
Rename DISABLE_Z_PROBE_ENDSTOP to DISABLE_Z_MIN_PROBE_ENDSTOP
Rename Z_PROBE_REPEATABILITY_TEST to Z_MIN_PROBE_REPEATABILITY_TEST
Rename Z_PROBE_ENDSTOP to Z_MIN_PROBE_ENDSTOP
Adjust comments accordingly
Remove Z_MAX  check for the probe in update_endstops().

Using an delta related idea of @clefranc from #61,
extended to the general change for all setups.

Tested with Prusa i3, max-z-endstop and permanently triggered z-probe.
Worked for @clefranc's delta.

The long descriptor will still be available in M115

Uses about 488 byte of progmem and 32 byte of RAM.
For that configurable.

- For some reason it’s easy to forget what BT stands for, but it
doesn’t need an abbreviation.

- `SD_DETECT_PIN` replaces `SDCARDDETECT`
- `SD_DETECT_INVERTED` replaces `SDCARDDETECTINVERTED`
- Revise the description of `SD_DETECT_INVERTED`
- Add a note about the override of `SD_DETECT_INVERTED` in
`Conditionals.h`

A speaker needs a AC or a pulsed DC to make a sound, a buzzer only needs a DC.
A buzzer has it's own resonator. It works in most cases to feed the buzzer with a pulsed DC, but the sound will not be as loud as with pure DC.

There seem to be boards where the BEEPER-pin is not able to handle a PWM. Obviously intended for a buzzer.
To make these board able to handle a speaker

* replace the PWM based tone()-function again with a on-delay-off-delay loop.

Hopefully the last time I touch the beeper code.

Just set up the pin. Don't move to a random position.

Simplify servo::move()
* servo::move() does not need the pin parameter - The pin is set during servo_init() with attach().
* servo::move() does not need a return value.

SERVO_LEVELING is the wrong condition to deactivate the servos.

Remove some temporary (Servo *) variables.
SanityCheck for the servo indexes.

by replacing the sequences (attach, write, delay, detach), and their conditions with the new function in Marlin.main.cpp
and removing the old configuration in the ABL part of Configuration.h

DEACTIVATE_SERVOS_AFTER_MOVE is ought to replace PROBE_SERVO_DEACTIVATION_DELAY.
But it will work on all servo moves, not only the probe servo moves.

Also clean up some trailing spaces in a few other sources

#defining something just to define something else doesn’t
make sense

If you want SDCARDDETECTINVERTED, just define it yourself.

If the previous code was intended to define, undefined and then again define the term, that code is improper.

The new define allows the sd card detect to be inverted or not from
Configuration.h

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.

Added the link to the github information about the
ELB_FULL_GRAPHIC_CONTROLLER

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

Moved SDCARDDETECTINVERTED and SDSLOW to Conditionals.h.
Added U8GLIB_LM6059_AF to define display specific actions.
Added reminder to compile in u8glib

Rename of define to avoid confusion between the controller and the
display which had similar names.

Fixes for some code formatting changes and commenting out the
ADAFRUIT_ST7565 define that was left defined.

Added support for new display type