fixed CSV example text to be clear about unique ID, closes #45

helios/templates/voters_upload.html

@@ -8,11 +8,18 @@
     If you would like to specify your list of voters by name and email address,<br />
     you can bulk upload a list of such voters here.<br /><br />
 
-    Please prepare a text file of comma-separated values, as follows:
+    Please prepare a text file of comma-separated values with the fields:
+</p>
+<pre>
+   &lt;unique_id&gt;,&lt;email&gt,&lt;full name&gt;
+</pre>
+
+<p>
+For example:
   </p>
   <pre>
       benadida,ben@adida.net,Ben Adida
-      bob,bob@acme.org,Bob Acme
+      bobsmith,bob@acme.org,Bob Smith
       ...
   </pre>