Series inferred from epub books are not sorted correctly

[tjarls]

I have noticed that series inferred from epub metedata use the wrong "Sort Name" and hence are often incorrectly sorted in the library view:

This is due to some logic in the scanner task that fills SeriesSort with TitleSort even for books that are part of series as opposed to one shot books where the title is promoted to series name. It'd be more accurate that, when an epub metadata provides an element with a series name, to use it as SeriesSort as well. As far as I can tell, calibre does not have a sorting key for series name, so there seems to be no property "file-as" associated with the "calibre:series" element.

[therobbiedavis]

@majora2007 I do agree with this approach. If the epub has a series, then it should fill that series name in the sort name, otherwise use the title name as the sort name.