Allow range facets to work across two fields #48
Description
In some instances it would be good to have the range facet work across two fields - e.g. in boardgames you have a minimum and maximum number of playes - so when selecting a range the Solr query should be somthing like:
min_num_players >= 2 and max_mum_players <=6
This can currently be done by setting a multi-valued field to be ranged upon, but each value must be placed into the multi-valued field for this to work.