disable nav until css is fixed

dev/book/theme/index.hbs

···
                 </div>
             </div>
 
+            {{#if false}}
             <nav class="nav-wide-wrapper" aria-label="Page navigation">
                 {{#if previous}}
                     <a rel="prev" href="{{ path_to_root }}{{link}}" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
···
                     </a>
                 {{/if}}
             </nav>
+	    {{/if}}
 
         </div>