Squashed '_vendor/src/github.com/peterbourgon/g2s/' changes from d09b870..ec76db4

ec76db4 '%s' => %q

git-subtree-dir: _vendor/src/github.com/peterbourgon/g2s
git-subtree-split: ec76db4c1ac16400ac0e17ca9c4840e1d23da5dc
Merge commit '866944c5de909befa84d3cecbc07f484d8bf6b2a' into fix-g2s-subtree-try2