Add a missing constant in 'radio_tx_status_t' enum
Merge pull request #1239 from rousselk/radio-API-again

Add a missing constant in 'radio_tx_status_t' enum
cleanup licenses to fix #392
Merge pull request #1217 from thomaseichinger/YALF

boards: cpu: cleanup licenses to fix #392
Initial commit of Arduino Mega2560
strip functions in atmega2560/periph and atmega_common/thread_arch.c down to prototypes

Add custom errno.h since avr-libc doesn't include one
rename board_init to main, main to o_main (inside hello-world/main.c). Fix
Makefile.include:

UART works within RIOT codebase, :)
Develop: fix invocation of avrdude