update to contiki 2.7
start porting hexabus stuff to stm32l
track contiki repo, clean skeleton a bit
restructure eeprom handling to be more sane and extensible

Conflicts:
	firmware/apps/provisioning/provisioning.c
move eeprom abstraction into own app
add STM32L support to the nvm app
remove cruft, put app init into one place
run contiki/rf230_init correctly on stm
enable leds
grah contiki .gitignore
...
fix apps for new platform
unify AVR and STM targets
update contiki
remove STM directory, use Device TARGET=Hexabus-STM instead
add "free ram" display to STM target
add a "Free RAM" display to the stm build
enable uart input
update contiki
minor header formatting