this PR replaces some bools with one char. this will safe 3 bytes and should also be sometimes a little bit faster.

delete some tabs

I.e., when acceleration * steps per mm > 2,000,000.
This was done by changing MultiU24X24toH16 to take a 32b bit operand.
Removed the claim that stepper.cpp uses the Leib algorithm.

- Potentially addressing #1911

Updated documentation in Configuration.h.
Cleaned up and commented some code relating to Z_PROBE_ENDSTOP.
Separated Z_MIN_ENDSTOP and Z_PROBE_ENDSTOP completely.

Documented some additional areas that should be addressed if Z_PROBE is
fully separated from Z_MIN or Z_MAX.
Fixed a documentation error in sanity checks. Servos start at 0 not 1.

This rolls back to commit 06f767d608.

- Fix `prepare_move` function not calling `adjust_delta`
- Add more shorthand for plan_buffer_line.
- Fix wrong `federate` usage, assuming they are all mm/m
- Minor `stepper.cpp` cleanup

Code cleanup for Z_PROBE_AND_ENDSTOP.
Added Z_PROBE_PIN to pins_RAMPS_13.h

- Add some documentation to planner and stepper headers
- Patch up RAMBO pins with undefs
- Add `sync_plan_position` inline to set current XYZE
- Swap indices in `extruder_offset` to fix initialization values

Typo fixes in comments in existing code.

- Patched up for most included configurations

- Fix a bug reading `code_value` for `M503 Sn`
- Hide and remove unused variables

Z_DUAL_ENDSTOPS is a feature to enable the use of 2 endstops for both Z
steppers - Let's call them Z stepper and Z2 stepper.
That way the machine is capable to align the bed during home, since both
Z steppers are homed.
There is also an implementation of M666 (software endstops adjustment)
to this feature.
After Z homing, this adjustment is applied to just one of the steppers
in order to align the bed.
One just need to home the Z axis and measure the distance difference
between both Z axis and apply the math: Z adjust = Z - Z2.
If the Z stepper axis is closer to the bed, the measure Z > Z2 (yes, it
is.. think about it) and the Z adjust would be positive.
Play a little bit with small adjustments (0.5mm) and check the
behaviour.
The M119 (endstops report) will start reporting the Z2 Endstop as well.

- Patch up macros in stepper.cpp

- Use named axis indexes, `X_AXIS` etc.
- Replace `block.steps_A` with block.steps[A]`
- Replace `A_segment_time` with `segment_time[A]`
- Add `A_AXIS`, `B_AXIS` for `COREXY` axes
- Conditional compile based on `EXTRUDERS`
- Add BLOCK_MOD macro for planner block indexes
- Apply coding standards to `planner.h` and `planner.cpp`
- Small optimizations of planner code
- Update `stepper.cpp` for new `block` struct
- Replace `memcpy` with loops, let the compiler unroll them
- Make `movesplanned` into an inline function

- Addressing #1625

- Add `Conditionals.h` with calculated configuration values
- Add `SanityCheck.h` with checks for configuration errors
- Remove equivalent code from all configurations
- Move error checks from some sources to `SanityCheck.h` also
- Fix initialization of count_direction in stepper.cpp

When one hit "Stop Print" option in LCD menu, the command buffer was not
cleared. The printer keep moving until the buffer has been emptied.
Actually I could not clear the command buffer as well.. I don't know
why, it doesnt work as expected.
I need to implement a routine inside Stepper ISR to handle such
situation.

The Check Endstop logic must be:

if (current_block->steps_x != current_block->steps_y || (TEST(out_bits,
X_AXIS) == TEST(out_bits, Y_AXIS)))
if (TEST(out_bits, X_HEAD))

not

if (TEST(out_bits, X_HEAD) && (current_block->steps_x !=
current_block->steps_y || (TEST(out_bits, X_AXIS) == TEST(out_bits,
Y_AXIS))))

Same applies for Y axis.

- Add BIT and TEST macros
- Add _APPLY_ macros to stepper.cpp to help with consolidation
- Consolidate code in stepper.cpp using macros
- Apply standards in stepper.cpp
- Use >= 0 instead of > -1 as a better semantic
- Replace DUAL_Y_CARRIAGE with Y_DUAL_STEPPER_DRIVERS

- Moved sanity-checks to Marlin_main.cpp
- Applied to other configuration files
- Fixed formatting of ABL output
- Passing verbose level to probe_pt
- Miscellaneous cleanup
- Put CONFIG_STEPPERS_TOSHIBA into Configuration.h

The X_Axis could not home to min while Y_Max endstop was trigged.

- Both TMC, L6470 and pin-driven drivers work.
- All can be mixed and matched as needed.