I don't think I explained when directory shows up clearly:

This is an actual snippet from telnetting into mpd and saying `listallinfo`

```
directory: P/Passion Pit/2008 - Chunk of Change [EP]
Last-Modified: 2013-01-05T03:53:00Z
file: P/Passion Pit/2008 - Chunk of Change [EP]/01 I've Got Your Number.mp3
Last-Modified: 2011-09-17T23:56:24Z
Time: 373
Artist: Passion Pit
AlbumArtist: Passion Pit
Title: I've Got Your Number
Album: Chunk of Change [EP]
Track: 1
Date: 2008
Genre: Indie
Composer: Michael Angelakos
Disc: 1/1
[ ... more songs ...]
file: P/Passion Pit/2008 - Chunk of Change [EP]/06 Better Things.mp3
Last-Modified: 2011-09-17T23:56:24Z
Time: 273
Artist: Passion Pit
AlbumArtist: Passion Pit
Title: Better Things
Album: Chunk of Change [EP]
Track: 6
Date: 2008
Genre: Indie
Composer: Michael Angelakos
Disc: 1/1
directory: P/Passion Pit/2009 - Manners
Last-Modified: 2013-01-05T03:53:00Z
file: P/Passion Pit/2009 - Manners/01 Make Light.mp3
Last-Modified: 2011-09-17T23:56:36Z
Time: 296
Artist: Passion Pit
AlbumArtist: Passion Pit
Title: Make Light
Album: Manners
Track: 1
Date: 2009
Genre: Electronic
Composer: Michael Angelakos
Disc: 1/1
```

Directory only shows up once per directory, not once per file. Following your suggestion `ListAllInfo` would have entries that are songs and entries that are directories. The directory entries would only have one other attribute, `Last-Modified`.

As for `directory` giving information about the directory hierarchy, I don't think it gives you anything. The hierarchy is already present in each song's `file` field. Using the `path/filepath` library can be used to get a file's directory (`filepath.Dir` specifically). 

Having the directory information in the returned Attrs list seems silly because two different types of information are being returned, masquerading as the same thing.

I think adjusting the `Last-Modified` filter to only exclude `Last-Modified` if the loop isn't currently in a song would be a good idea. It seems the issue with Last Modified was that it shows up with directory, before a file is started.