The registers within the Max7219 can get corrupted a number of ways. This allows the Max7219 to be reset and fully initialized.
And... it also allows the user to see the initialization pattern.
Same as #7728 but for 2.0.x,
Lot of cleanup and remove references in whole code to other "LED files" than leds.h. Now will be much easier to add next drivers/libraries. e.g. FastLED. But bad news, currently FastLED is suporting only RGB devices (no RGBW)