ontology doesn't show up in WebVowl

[VladimirAlexiev]

https://lov.linkeddata.es/dataset/lov/vocabs/era shows this link in top right:
https://service.tib.eu/webvowl/#iri=http://data.europa.eu/949/

Unfortunately, WebVowl only shows GeoSPARQL classes and props, and a couple more external classes.
It doesn't show any ERA class or property.

This might be related to proper ontology resolution and serving (#27)