This is mostly for less confusion, because analog pins can
be used as digital ones, too. It also matches what other firmwares
do, so people can simply copy & paste pin definitions.
Definitions were taken from Sprinter's fastio.h (which was
initially crafted by copying Teacup's arduino*.h files :-) )
Eventual debugging LEDs aren't part of the CPU, but part of the
electronics. Accordingly, define it in config.*.h, not in
arduino_*.h (which would be better named something like
"atmega_*.h).
Markus Hitter
Mikko Sivulainen
Michael Moon