Add support for ATtiny88, ATmega32HVB, ATmega1284P.
Fix support for AT90USB82/162, move them into "avr35" architecture.
Add support for the OS_main and OS_task attributes.
Integrate some more bugfixes from the WinAVR patch list.
Copy over the avr-gcc-devel port to avr-gcc, so this will become the
default AVR-GCC version now.
No repocopy as this port used to exist before. For the history details,
see the old avr-gcc-devel port (going to be moved to Attic now).