Re-tagged items appearing in Recently Added

[simoncn]

When the "recently added" list is first created, albums will probably have been added in the previous few days or weeks. Most users would be surprised not to see any of these albums but see an empty list instead.

MinimServer takes care to only include these additional files if they have "last modified" dates that are older than all the "added by rescan" files in the list. This ensures that no "possibly retagged" files are shown above any "added by rescan" files in the recently added index.