Some of the Rotations did not do the right thing with setting and clearing pixels.
I think it is correct now.   But if not...  It is much closer to being correct.

* Add Multi Unit Support for Max7219 to bugfix_2.0.0

* Apply multi-MAX7219 to example configs

* Tweak some spacing, macros

Also, Max7219 debug code was used for this effort.   It has been
improved and hardened.

* 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...

* 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.