#970 Display translated INTERIORART titles as variants in Publication listing

[Ahasuerus]

As per http://www.isfdb.org/wiki/index.php/ISFDB:Community_Portal#Change_in_the_publication_view and http://www.isfdb.org/wiki/index.php/User_talk:Ahasuerus#interior_artwork_as_translation:

At the moment, when the variant of a title has a different language than the original, the software renders that as a translation in the publication content view. When the variant is an Interior Art, that does not look accurate. So the proposal is to treat is a variant and not as a translation so in Bilbon viimeinen laulu:
instead of
Bilbon viimeinen laulu • interior artwork by Pauline Baynes (trans. of Bilbo's Last Song 1990)
we will get
Bilbon viimeinen laulu • interior artwork by Pauline Baynes (variant of Bilbo's Last Song 1990)

[Ahasuerus]

Implemented in biblio/pl.py 1.98, installed in r2017-017 on 2017-01-13. Closing.