Designating a folder in which composer tags should be submitted instead of artist tags

[ghost]

Not sure if this is useful for everyone, but: for classical music, the
composer field is what Last.fm will want to receive.

If classical music files have correct tags (meaning a composer as a
composer, and a performer as an artist), setting the config option

composerfolder = "path/holding/classical-music"

will submit composer instead of artist.

E.g. Alfred Brendel playing a Beethoven sonata:

composer: Ludwig van Beethoven
artist: Alfred Brendel
title: Sonata

will submit "Ludwig van Beethoven - Sonata" to Last.fm, if the file in
question is in the folder designated as composerfolder.