Add verbatim tag

[toptalo]

Address issue #571

The verbatim tag marks sections as being raw text that should not be parsed. For example to put Twig syntax as example into a template you can use this snippet:

{% verbatim %}
    <ul>
    {% for item in seq %}
        <li>{{ item }}</li>
    {% endfor %}
    </ul>
{% endverbatim %}

[toptalo]

Thanks!