Revert 756b346fc7fd7e936a0f27bbb9a3f09a9833db4a,
use avr/wdt.h for watchdog handling, which guarantees
timing compliance for configuration, no need to keep
separate options for various files now.
Makefile cosmetics.
Correct layout of board in features file.
Change ISR's to nonblock, to avoid missing interrupts.
Cosmetics + add disable internal pull-up resistors on all ports.
Add checksum errors to stats.
Explanation for extra SPI reset.
Change SPI clock to from /16 to /4 = 2 Mhz, should work equally well.
LED reassignments, cosmetics.