define radiopacket_length_t in board.h
switch thread instead of exiting context

lpm_sleep is always being called from within a thread context, not
from an isr context, therefore it should use thread_yield instead of
cpu_switch_context_exit.
handle stdin EOF
Merge pull request #34 from LudwigOrtmann/fix_native_handle_uart0_input

switch thread instead of exiting context, handle EOF
Merge pull request #32 from mehlis/radio-packet

define radiopacket_length_t in board.h
fixed missing stdint includes for all platforms

 * plus some minor include and prototype fixes for wsn430
Merge pull request #30 from thomaseichinger/uart_fixes

fix for the mc1322x uart
added missing header guard to native board.h
Merge pull request #36 from OlegHahm/include_fixes

fixed missing inttypes includes for all platforms
Fixed typo in avsextre/include/board.h include
Merge pull request #38 from haukepetersen/avsextrem-fix

Fixed typo in avsextre/include/board.h include
mc1322x moved radio implementation