Feature
* Use PackageablePath and ListOption in more places ([`c2ae76d`](https://github.com/mcbeet/beet/commit/c2ae76db4e29c074279a2316fd6b565c8f9fd8ea))
* Improve config overrides and add tests ([`228f034`](https://github.com/mcbeet/beet/commit/228f034bf98662341ee372f93e99315133251d76))
* Generalize packageable paths ([`b5ad8f0`](https://github.com/mcbeet/beet/commit/b5ad8f04feb2e3aa46780969a615b653550566e8))