This patch will fail to apply when a new version comes out, and thus
will force us to remove it, where the `sed` command in `postPatch` may
become abandoned, and not fail the build due to it not doing anything.
Highlights:
* We now have a beets-unstable
* We now run tests for beets-minimal
* We're much more strict about the effects of enabling/disabling plugins
* All patches but one were dropped
* Removal of deprecated nose in favor of pytest
* Art resizing is working better now
