As suggested by https://github.com/MarlinFirmware/Marlin/pull/5887#issuecomment-283832163

Work around for slicers producing buggy gcode.

Resolves #5926. This override is no longer needed since the RAMPS LCD controller pins were fixed.

In the endstop testing section, add the "reverse" logic in addition to "normal" core handling.

In CoreXY/YZ/XZ steppers rotating the same direction gives X movement. Opposing directions produces Y movement.

In CoreYX/ZY/ZX this is reversed. Same = Y, Opposite = X.

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Fixes the issue where the Y endstop was being checked when moving in the X direction, etc.

As suggested in
https://github.com/MarlinFirmware/Marlin/issues/5570#issuecomment-283059
065

- Add configuration support for zigzags in either the X or Y axis, for
wipe pads significantly longer in one dimension.
- Add configuration for default number of zig-zag triangles, vs. a
magic number in `Marlin_main.cpp`.
- Update description of auto nozzle wiping to match functionality

Also add a hotend indicator to the heating message displayed on the lcd status line.

Followup to #5840

LCD call was waiting forever, causing the system to hang.

If Marlin is inside the temperature ISR, the stepper ISR is enabled. If
a stepper event is now happening Marlin will proceed with the stepper
ISR. Now, at the end of the stepper ISR, the temperatre ISR gets enabled
again. While Marlin proceed the rest of the temperature ISR, it's now
vulnerable to a second ISR call.

Hopefully fixes Marlin #5481

Addressing #5806