Based on #7769

Melzi fixes

Fixed typo where ST7920_DELAY_2 was being #defined after a check for #ifndef ST7920_DELAY_3

Sanity Check for LCD_FOR_MELZI  would fail with "Please select no more than one LCD controller option" any time #define LCD_FOR_MELZI was enabled in Configuration.h, even if there were no other LCD options enabled.

[1.1.x] Fix G3D_PANEL encoder steps, babystep label

Ideally, it should be calculated based on Z steps per unit so that each
babystep corresponds to around 0.025mm. Smaller than this is largely
insignificant for typical layer heights.

As pointed out by @marcio-ao in #7638

More featureful CR-10 configurations

* matrix names update

* symplified names

* new angle normalization

* ABC

* axis

* least squares

* recalc_delta_settings

* endstop_adj

* 0p

* bug

Fix caselight compile issues

Replaced extruder with hotend

Added option for graphical overlay for Z-offset (Resubmission of #7350 and #7586)

M111: no args reports current flags

CNC workspace planes for G5

According to LinuxCNC, G5 should throw an error if the current plane mode isn't XY.

* Add MAX7219_DEBUG to Travis CI testing

* Tweak config and use standard pin naming for MAX7219_DEBUG

* MAX7219: Apply coding standards, use macros, etc.

* Make code work...

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Fixes required for Creality CR-10

* Add Max7219 LED Matrix Debug Support

The Max7219 8x8 LED Matrix's are very helpful for debugging new code.
And for that matter, just trying to maximize printer settings without
causing stuttering.

The displays are very inexpensive (under $2.00 with shipping) and
provide a lot of help when trying to debug complicated code.

* Try to keep Makefile up to date.

Addressing #7552

When M405 is used it changes 'volumetric_multiplier[FILAMENT_SENSOR_EXTRUDER_NUM]' value. When M406 disables M405 it leaves the value unchanged.
This PR applies 'calculate_volumetric_multipliers' in M406 instead of resetting it to 1.0 because M200 may not be compatible with M405 hence I'm sure to restore anyway with correct value.

New feature: Part-Cooling Fan Multiplexer

Sanguinololu example config

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