HTTPS links to github, gitblab and bitbucket and add www to facebook (m…

…mistakes#1349)

GitHub, Gitlab and Bitbucket are all always served over HTTPS.
Facebook links always have www.

_includes/footer.html

@@ -7,16 +7,16 @@
       <li><a href="https://twitter.com/{{ site.twitter.username }}"><i class="fa fa-fw fa-twitter-square" aria-hidden="true"></i> Twitter</a></li>
     {% endif %}
     {% if site.facebook.username %}
-      <li><a href="https://facebook.com/{{ site.facebook.username }}"><i class="fa fa-fw fa-facebook-square" aria-hidden="true"></i> Facebook</a></li>
+      <li><a href="https://www.facebook.com/{{ site.facebook.username }}"><i class="fa fa-fw fa-facebook-square" aria-hidden="true"></i> Facebook</a></li>
     {% endif %}
     {% if site.author.github %}
-      <li><a href="http://github.com/{{ site.author.github }}"><i class="fa fa-fw fa-github" aria-hidden="true"></i> GitHub</a></li>
+      <li><a href="https://github.com/{{ site.author.github }}"><i class="fa fa-fw fa-github" aria-hidden="true"></i> GitHub</a></li>
     {% endif %}
     {% if site.author.gitlab %}
-      <li><a href="http://gitlab.com/{{ site.author.gitlab }}"><i class="fa fa-fw fa-gitlab" aria-hidden="true"></i> Gitlab</a></li>
+      <li><a href="https://gitlab.com/{{ site.author.gitlab }}"><i class="fa fa-fw fa-gitlab" aria-hidden="true"></i> Gitlab</a></li>
     {% endif %}
     {% if site.author.bitbucket %}
-      <li><a href="http://bitbucket.org/{{ site.author.bitbucket }}"><i class="fa fa-fw fa-bitbucket" aria-hidden="true"></i> Bitbucket</a></li>
+      <li><a href="https://bitbucket.org/{{ site.author.bitbucket }}"><i class="fa fa-fw fa-bitbucket" aria-hidden="true"></i> Bitbucket</a></li>
     {% endif %}
     <li><a href="{% if site.atom_feed.path %}{{ site.atom_feed.path }}{% else %}{{ '/feed.xml' | absolute_url }}{% endif %}"><i class="fa fa-fw fa-rss-square" aria-hidden="true"></i> {{ site.data.ui-text[site.locale].feed_label | default: "Feed" }}</a></li>
   </ul>