Delete playlist from server

[mitchdowney]

Now that playlists are automatically retrieved based on userId in the mobile app, my userId is full of test playlists that I don't want that I'd like to delete.

The ability to delete a playlist from the server based on playlistId will be useful eventually. Until there's auth though it may not be necessary.

[mitchdowney]

Deleting clips or playlists can be added if people request it...