Conditional child inclusion 140

Merged the branch from this PR into this branch:

https://github.com/walmartlabs/thorax/pull/181

as it would have caused merge conflicts. Relevant commits for this PR:

- https://github.com/walmartlabs/thorax/commit/c9bfcdfe7ecc27f0ad16ff020a3c25390d6c5630
- https://github.com/walmartlabs/thorax/commit/287091cd6b8200f583b6d480e2f54f2b4a520576