def render_string string, options
      escaped = html_escape(string)
      if options[:pretty]
        indent = ' ' * (options[:indent] * options[:depth])
        indent + escaped + "\n"
      else
        escaped
      end
    end
def render_string string, options
      escaped = html_escape(string)
      if options[:pretty]
        indent = ' ' * (options[:indent] * options[:depth])
        indent + escaped + "\n"
      else
        escaped
      end
    end
html-escape a string, paying attention to indentation too.