Squashed 'sequence/' changes from e5625c6..0d721a6

0d721a6 release 0.5.2
a50f307 merge from master
81d7315 bugfix: take would fail on 0
4ae9e77 Merge pull request #5 from Drup/master
ae390d3 Add on_list.

git-subtree-dir: sequence
git-subtree-split: 0d721a63515949fe564552c98895780d86fc2a98
Merge commit '15665761b2d85469c1f0591cb976ba6956100cc5' for sequence