remove twitter mention

Author: Carreau

nbviewer/templates/notebook.html

@@ -35,15 +35,6 @@
 
   {# Twitter Card #}
 
-  {# Required fields #}
-  <meta name="twitter:card" content="summary">
-  <meta name="twitter:title" content="{{ notebook_title | default('Notebook on nbviewer') }}">
-  <meta name="twitter:description" content="{{ description | default('Check out this Jupyter notebook!') }}">
-
-  {# Optional fields #}
-  <meta name="twitter:domain" content="nbviewer.jupyter.org">
-  <meta name="twitter:image:src" content="{{ thumbnail | default('http://ipython.org/ipython-doc/dev/_images/ipynb_icon_128x128.png') }}">
-
   {% block style_base %}
     <link href="{{ static_url("build/notebook.css") }}" rel="stylesheet">
   {% endblock %}