Merge branch 'fix-plotly' into 'master'

Fix plotly plots

Closes #61

See merge request !48

.gitlab-ci.yml

@@ -7,7 +7,7 @@ stages:
 build lectures:
   stage: build
   before_script:
-    - pip install -U mkdocs mkdocs-material python-markdown-math notedown
+    - pip install -Ur requirements.txt
   script:
     - python execute.py
     - mkdocs build

extra_markdown.tpl

@@ -22,7 +22,11 @@
 {% else %}
 <pre class="thebelab-code" data-executable="true" data-language="python">{{cell.source}}</pre>
 <div class="thebelab-output" data-output="true" markdown="1">
+{% if output.data['text/html'] %}
+{{ output.data['text/html'] }}
+{% else %}
 {{ super() }}
+{% endif %}
 </div>
 {% endif %}
 {% endblock %}