Squashed 'floo/common/' changes from e415ce1..6e85819

6e85819 Merge common. Fix conflict.
bc039ff Simpler reactor.block
7cdbfdc Merge commit '9e943d095f7cf404217cf90f9f5367716dd8849a'
e808f26 Merge common fixes.

git-subtree-dir: floo/common
git-subtree-split: 6e858191c33a30eb696a80655d8044c3c63ba624
Merge commit '8285671241dc417076568ea2a7f36ee58b19fe07'
Remove empty py file.