Improve screen reader accessibility of table (#339)

Author: lisicase

pages/reference-service.html

@@ -6,13 +6,13 @@
 ---
 <div id="services-tab">
 <ul class="nav nav-tabs" role="tablist" aria-label="Versions"> 
-  <li role="presentation" class="active">
+  <li class="active">
     <a class="tab-link" href="#odata-v4" role="tab" aria-controls="odata-v4" data-toggle="tab">OData v4</a>
   </li>
-  <li role="presentation">
+  <li>
     <a class="tab-link"  href="#v3" role="tab" data-toggle="tab" aria-controls="v3" tabindex="-1">OData v3</a>
   </li>
-  <li role="presentation">
+  <li>
     <a class="tab-link" href="#v2" role="tab" data-toggle="tab" aria-controls="v2" tabindex="-1">OData v2</a>
   </li>
 </ul>