Squashed 'contiki-tres/' content from commit 1b68b4e

git-subtree-dir: contiki-tres
git-subtree-split: 1b68b4e76286fce57ebbca1335103ed522396184
Merge commit 'c6f2b3398d0bafd9bdd2fcff9c5c2b470e5db186' as 'contiki-tres'
fixed celeryapp config and other minor things