Squashed 'contiki/' content from commit 8bcd8a4

git-subtree-dir: contiki
git-subtree-split: 8bcd8a428c18f5a34d92f0c7ec75df6d706eef5c
Merge commit '81d367971f9c6f82859cd7cf1e0214c92cc788cb' as 'contiki'