Error when previewing an empty new compendium (presumably)

Internal Server Error: /preview/
Traceback (most recent call last):
  File "/home/wikipendium-web/wikipendium.no/venv/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 132, in get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/wikipendium-web/wikipendium.no/venv/local/lib/python2.7/site-packages/newrelic-2.54.0.41/newrelic/hooks/framework_django.py", line 499, in wrapper
    return wrapped(*args, **kwargs)
  File "/home/wikipendium-web/wikipendium.no/venv/local/lib/python2.7/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view
    return view_func(*args, **kwargs)
  File "./wikipendium/wiki/views.py", line 255, in preview
    html = article_content.get_html_content()
  File "./wikipendium/cache/decorators.py", line 48, in inner
    return fn(*args, **kwargs)
  File "./wikipendium/wiki/models.py", line 194, in get_html_content
    'toc': md.toc,
AttributeError: 'Markdown' object has no attribute 'toc'

Request repr():
<WSGIRequest
path:/preview/,
GET:<QueryDict: {}>,
POST:<QueryDict: {u'content': [u'']}>,
COOKIES:{'_ga': '*',
 '_gat': '1',
 'csrftoken': '*',
 'sessionid': '*'},
META:{'CONTENT_LENGTH': '8',
 'CONTENT_TYPE': 'application/x-www-form-urlencoded; charset=UTF-8',
 u'CSRF_COOKIE': u'*',
 'DOCUMENT_ROOT': '/etc/nginx/html',
 'HTTPS': 'on',
 'HTTP_ACCEPT': '*/*',
 'HTTP_ACCEPT_ENCODING': 'gzip, deflate',
 'HTTP_ACCEPT_LANGUAGE': 'nb-NO,nb;q=0.8,no;q=0.6,nn;q=0.4,en-US;q=0.2,en;q=0.2',
 'HTTP_CONNECTION': 'keep-alive',
 'HTTP_CONTENT_LENGTH': '8',
 'HTTP_CONTENT_TYPE': 'application/x-www-form-urlencoded; charset=UTF-8',
 'HTTP_COOKIE': '*',
 'HTTP_HOST': 'www.wikipendium.no',
 'HTTP_ORIGIN': 'https://www.wikipendium.no',
 'HTTP_REFERER': 'https://www.wikipendium.no/new/',
 'HTTP_USER_AGENT': 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/47.0.2526.111 Safari/537.36',
 'HTTP_X_REQUESTED_WITH': 'XMLHttpRequest',
 'PATH_INFO': u'/preview/',
 'QUERY_STRING': '',
 'REMOTE_ADDR': '*',
 'REMOTE_PORT': '*',
 'REQUEST_METHOD': 'POST',
 'REQUEST_URI': '/preview/',
 u'SCRIPT_NAME': u'',
 'SERVER_NAME': 'www.wikipendium.no',
 'SERVER_PORT': '443',
 'SERVER_PROTOCOL': 'HTTP/1.1',
 ...
 >
wikipendium / wikipendium.no

Error when previewing an empty new compendium (presumably) #435
