Merge branch 'master' into canary

Merge remote-tracking branch 'origin/master' into canary

Merge remote-tracking branch 'origin/master' into canary

Merge tag '1455221833212' into release

Merge tag '1455166600475' into release

Merge remote-tracking branch 'origin/master' into canary

Merge remote-tracking branch 'origin/master' into canary

Merge branch 'master' of github.com:ampproject/amphtml into canary

Merge remote-tracking branch 'upstream/master' into canary

Merge tag '1454726798143' from canary into release