add test_vtimer_msg
Merge pull request #45 from benpicco/master

add test_vtimer_msg
radio_packet_length_t, coding conventions

use radio_packet_length_t to allow for packets > 255 byte
make includes adhere to codiing convention
Merge pull request #52 from LudwigOrtmann/default-native-update

radio_packet_length_t, coding conventions
Companion commit to PR #282