Add a globe icon for personal website badges.

This icon comes from https://github.com/twitter/twemoji/blob/ad3d3d669bb3697946577247ebb15818f09c6c91/assets/svg/1f310.svg, licensed CC-by-4.0. In the readme, it says "We would consider a mention in the HTML/JS source sufficient also." so that is what we did.

I tweaked the color of the path to a dark grey, matching the text on the page.

Author: jasongrout

_includes/biocard.html

@@ -13,7 +13,7 @@
     {% endif %}
     <div class='biocard-badges'>
       {% if include.personal %}
-        <a href="{{ include.personal }}" rel="noopener noreferrer">Web</a>
+        <a href="{{ include.personal }}" rel="noopener noreferrer"><img src="/assets/badges/1f310.svg" alt="Personal Website"></a>
       {% endif %}
       {% if include.gh_handle %}
         <a href="https://github.com/{{ include.gh_handle }}" rel="noopener noreferrer"><img src="/assets/badges/github.svg" alt="GitHub"></a>

about.html

@@ -670,5 +670,5 @@ <h2 class="text-center">{{ page.donate_box.headline }}</h2>
         </a>
     </div>
   </div>
-
+  <!-- The globe icon is originally from https://github.com/twitter/twemoji/blob/ad3d3d669bb3697946577247ebb15818f09c6c91/assets/svg/1f310.svg, licensed CC-by-4.0 -->
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