Merge pull request #1 from adamrenner/contiki_mod

Contiki mod
Merge branch 'master' of github.com:adamrenner/mqtt-sn-tools-contiki
Changed license to MIT
Merge branch 'contiki_mod'
Merge remote-tracking branch 'upstream/master'

Conflicts:
	mqtt-sn-pub.c
	mqtt-sn-sub.c
licensing changes fixed to match mqtt-sn-tools changes