Revert back to html5lib==0.999. Add commented links explaining why.

Author: mrmachine

setup.py

@@ -67,7 +67,7 @@ def find_packages(*paths):
         'django-polymorphic',
         'django-wysiwyg',
         'django_extensions',
-        'html5lib',
+        'html5lib==0.999',  # See: https://github.com/html5lib/html5lib-python/issues/189 and https://github.com/pydanny-archive/django-wysiwyg/issues/61
         'nltk',
         'Pillow',
         'pip-tools',