Abstract idea of Song instead of pure file management

[Jud Craft]

One last thing -- this is extremely forward thinking:

If it is possible, make it so that we can associate different files
with a Song, and not just music files.  My details are as follows.

This may come in handy later, when you want to begin grouping
ontologic (a buzzword I may not understand) content with songs -- for
example, we may wish to associate sheet music graphics with a song,
those cool little PDF insert guides that come with some albums, or
other pieces of content.

I might say, generically modify the database so that you can associate
any file with an album based on album/year metadata.  I know that
currently we tag song files, and then amarok groups them by artist and
album metadata.  Make it so that instead of just song files, entries
for any file can be added (but of course only music files can be
played) to the database.

This means that A) instead of just song files, we can now associate
any file with an album, and B) any Song-specific set of associated
files may now be grouped under the abstract idea of a Song/Track.

I would not get hung up on huge feature lists to make use of this
expanded capability:  for now, I would concentrate on the Song
source-file-association part.  But I believe it may be a relatively
insignificant change to the Amarok database design to group not just
song files by album/artist, but _any_ file, and if you make this
change early in Amarok's lifetime, there will be huge potential for
expansion later.

This last idea may well be called "Song Content Abstraction" as
opposed to "Song Source Abstraction", and perhaps it can wait until
Amarok 3.  I feel bad possibly derailing the topic with such an idea,
but since it is closely related to abstracting song-associated content
(of which the music file itself is just one type of content), I felt
it is worth mention.