title: Disable all cookies in oTree
body: <p>In oTree, two cookies are created:
  <code>sessionId</code> and <code>csrf_token</code>.</p>
  <p>I want to disable both; however, I don't know how to do that.</p>
  <p>I know that when I use <code>participant_label</code> in the URL, I can avoid the <code>sessionId</code>-cookie. However, then I still have the <code>csrf_token</code>-cookie.</p>
  <p>Do you know how to unset it? I heard that <a href="http://pypi.org/project/django-cookieless" rel="nofollow noreferrer">django-cookieless</a> should be a solution, but I don't know how to use that.</p>