Added an event to get linked resources via subject values.

[Daniel-KM]

Some people want to order subject values not by title, but by something else, for example by bibo:volume and bibo:issue. The feature is already implemented in module Advanced Resource Template, but an event is needed for that.

[jimsafley]

Thanks for this. I can see this being helpful.

I see that you're differentiating the events by an isSimple argument. We prefer that you use distinct names instead: api.subject_values.query and api.subject_values_simple.query.

[Daniel-KM]

Ok.

[zerocrates]

Thanks.