Remove sharethis.com from header and chen's profile. Was causing erro…

…rs/warnings

_includes/head.html

@@ -52,8 +52,6 @@
     {%- endif -%}
     {%- include head-scripts.html -%}
 
-    <!-- Added by Chen -->
-    <script type='text/javascript' src='https://platform-api.sharethis.com/js/sharethis.js#property=5ee902d30e78e50012567eb4&product=inline-follow-buttons&cms=sop' async='async'></script>
 
     <!-- for mathjax support -->
     {% if page.usemathjax %}

_team/alumni/chen.md

@@ -29,13 +29,3 @@ He is currently serving as an Associate Editor for IEEE Robotics and Automation
     - <[email protected]> (Preferred)
     - <[email protected]>
 
-- Follow Chen Wang elsewhere:
-    <div class="sharethis-inline-follow-buttons"></div>
-
-<a class="twitter-timeline"
-        data-tweet-limit="5"
-        data-theme="light"
-        width="100%"
-        href="https://twitter.com/DrChenWang">News from Twitter @DrChenWang<br>You need VPN if you see this.
-</a>
-<script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>