Move class_icon providers filtering out of TagRegistry.

      @html_renderers_sorted = false

      @member_types = []

      @css = []

      @class_icon_providers = []

      @tags = []

      instantiate_tags(TagLoader.new(load_paths).load_all)

    end

          @css << tag.css

        end

        if tag.class_icon

          @class_icon_providers << tag

        end

        @tags << tag

      end

    end

    # (and in order they should be shown in).

    attr_reader :signatures

    # Array of tags which provide icons for classes.

    attr_reader :class_icon_providers

    # Array of all available tags

    attr_reader :tags

    # Same as #member_types, but returns just the names of member types.

    def member_type_names

      end

      def self.class_icon_providers

        @providers ||= TagRegistry.class_icon_providers.sort do |a, b|

        @providers ||= generate_class_icon_providers

      end

      # Find tags with #class_icon and sort them from highest priority to lowest

      def self.generate_class_icon_providers

        TagRegistry.tags.find_all {|t| t.class_icon }.sort do |a, b|

          a.class_icon[:priority] <=> b.class_icon[:priority]

        end.reverse

      end