remove duplicate files

[fedelibre]

I've lost some time updating the syntax of files in the collections/ directory which are already update under ftp/. It's Mozart KV487. For example:

$ git grep 'piece = "No. 12.  Allegro"'
collections/kv487/kv487-lys/no12.ly:109:    piece = "No. 12.  Allegro"
ftp/MozartWA/KV487/no12/no12-lys/no12.ly:124:    piece = "No. 12.  Allegro"

I guess that the whole collections/kv487 should be deleted.
Perhaps others. I hope someone can double check and confirm.