def to_html(options={})
      lineHtmls = @lines.map{|x| x.to_html(options)}
      "<div class=\"#{css_class_names}\">\n  " + 
        (@languageTitle ? "<div class=\"language\">#{@languageTitle}</div>\n  " : "") +
        lineHtmls.join("").chomp("\n").gsub("\n", "\n  ") +
        "\n</div>\n"
    end
def to_html(options={})
      lineHtmls = @lines.map{|x| x.to_html(options)}
      "<div class=\"#{css_class_names}\">\n  " + 
        (@languageTitle ? "<div class=\"language\">#{@languageTitle}</div>\n  " : "") +
        lineHtmls.join("").chomp("\n").gsub("\n", "\n  ") +
        "\n</div>\n"
    end
Convert to HTML as a *<div>* with CSS class determined by *css_class_names*.
 Include a *<div>* of CSS class "language" (if the language title is given)
 Include HTML for the lines, converted according to the options for Helpers::text_to_html).