Abstract idea of Song instead of pure file management

[Jud Craft]

Ah.  I stand corrected.

Another benefit of doing tag-only matching is the speed of
development.  It provides an easy way to begin prototyping the ability
of the database to abstract song files.

With two possible mechanisms for comparison (tag-matching and
deep-song-analysis), the former is very quickly implemented, though of
course it has slightly different functionality and use cases from the
latter.

Which means you can quite quickly move past the "How can I compare two
files?" and more to the "Now how will our database manage these
files?"  Later, a song-analysis comparison mechanism could be added to
give additional functionality to the song comparison backend.