Add Google sponsor at end.

www/conservancy/static/supporter/event.html

@@ -108,4 +108,8 @@
 <span id="form-correction-needed" class="form-error">Please ensure all form data above is correct.</span>
 </div>
 
+<p>Event sponsored in part by:<br/>
+<a href="http://google.com"><img src="/img/sponsors/google.png" height="76"
+                                 width="238" alt="Google" /></a></p>
+
 {% endblock %}