Automatically determine if filename lengths in the Books directory are limited to 255 UTF-16 characters (NTFS) or 255 UTF-8 bytes (pretty much every other file system) (#1260)
In non-Windows environments, determine if the Books directory supports filenames containing characters which are illegal in Windows environments (<>|:*?). If it doesn't, then ensure those characters are included in the user's ReplacementCharacters settings (#1258).
