Close html tags (#678)

* faq.html: close a tag
* 404/500.html: close div tag

Author: pjonsson

wwwroot/404.html

@@ -68,6 +68,7 @@ <h2>That page doesn't seem to be here</h2>
     </div>
 
 
+        </div>
         </div>
         <!-- Footer -->
 <footer class="footer">

wwwroot/500.html

@@ -67,7 +67,7 @@ <h2>Internal server error</h2>
     </div>
     </div>
 
-
+        </div>
         </div>
         <!-- Footer -->
 <footer class="footer">

wwwroot/help/faq.html

@@ -221,7 +221,7 @@ <h4 class="panel-title">
     </div>
   </div>
 
-  <h2 class="faq-grouping"><a class="anchor" name="nm-systemdata">NationalMap system and data</h2>
+  <h2 class="faq-grouping"><a class="anchor" name="nm-systemdata">NationalMap system and data</a></h2>
 
   <div class="panel panel-default">
     <div class="panel-heading" role="tab" id="headingEight">