Multi-disc DiscSubtitle sorting

[simoncn]

It is an error to have two different DISCSUBTITLE tags for files that are part of the same album and have the same DISCNUMBER. MinimServer checks for this when the conflicting files are in the same folder but there is currently no check for this when the conflicting files are merged from different folders into the same album disc. I will add this check in the next update.

I hadn't expected that anyone would use the same DISCSUBTITLE for different discs of the same album. This should work OK. The DISCSUBTITLE value is purely cosmetic and doesn't affect merging etc.

At present, you are trying to have two separate discs in the same album, both numbered as disc number 1. This isn't possible with MinimServer and you will need to tag the CD as either a separate album or disc number 5.

Another approach that you might (or might not) find useful is to tag the CD as part of the multidisc album but without any DISCNUMBER or DISCSUBTITLE. This effectively creates a "disc 0" that is shown before disc 1 in the multidisc album browse view.