Add feature and add For plugin developers.
Add feature and add For plugin developers.

shamangeorge/beets,jackwilsdon/beets,ibmibmibm/beets,ibmibmibm/beets,jackwilsdon/beets,jackwilsdon/beets,beetbox/beets,SusannaMaria/beets,shamangeorge/beets,jackwilsdon/beets,beetbox/beets,ibmibmibm/beets,SusannaMaria/beets,shamangeorge/beets,shamangeorge/beets,sampsyo/beets,sampsyo/beets,SusannaMaria/beets,SusannaMaria/beets,beetbox/beets,sampsyo/beets,ibmibmibm/beets,beetbox/beets,sampsyo/beets