Muliple facets not possible

[NicolasGoeddel]

I need to search for multiple facet fields. But because of the dict parameters used in collective.solr.search.search() and collective.solr.solr.search() it is not possible to use more than one key with the same name, in this case facet.field. But as you can read here it is possible to ask Solr for more than one facet at a time.

It seems there have to be changed many things in order to allow faceting with multiple fields.