7.x various updates

- Fix for broken date range sliders: every date range field that has the slider enabled, set the minimum facet results to 0 so we always return empty dates as well. This fixed the date range calculation as well though a small fix needed to applied.
- Showing date range settings made dependent on the Solr field being a 'date' type. This will need to updated when we want to use integers for our range facets.
- Fixed the way default sort fields are applied.
- Added possibility to format date fields in Solr results.
- Don't include highlighting Solr parameters if no fields are set to be highlighted. This would slow Solr calls down.
- Fixed minor date range values formatting in breadcrumbs and current query.