require nokogiri 1.6+
fix devise under rails 3.x
provide a SOLR_URL ENV variable to set the location of the development solr core
make blacklight_config an optional argument to the solr field configuration
don't use render_filter_value in render_search_to_s_element (because it's given a value pre-wrapped and html-safe already)
use facet_configuration_for_field to render search history constraints, so they work even if the facet field is not configured