Print filenames when logging Markdown formatting.

      class_formatter.include_types = !@opts.export

      # Format all doc-objects in parallel

      formatted_classes = @parallel.map(@relations.classes) do |cls|

        Logger.instance.log("Markdown formatting #{cls[:name]}")

        files = cls[:files].map {|f| f[:filename] }.join(" ")

        Logger.instance.log("Markdown formatting #{cls[:name]}", files)

        begin

          {

            :doc => class_formatter.format(cls.internal_doc),

            :images => doc_formatter.images

          }

        rescue

          Logger.instance.fatal("Error while formatting #{cls[:name]}", $!)

          Logger.instance.fatal("Error while formatting #{cls[:name]} #{files}", $!)

          exit(1)

        end

      end