Via Tender: language query should include null and empty values in the result

Assigned to Tender discussion #864. As reported in Tender:

When querying for images a lot of backdrops and posters are not included because they have no language set.
Would it be a good idea to include those with an empty value or null in the result and consider them 'global' (available to all languages) ?

iso_639_1 iso_639_1

Or would it be possible to include some kind of multiple selector syntax.

For example to search for english, empty and null results we could do it like this
http://api.themoviedb.org/3/movie/1271/images?api_key=&language=en;;null;