Add align to root index file.

index.html

@@ -56,7 +56,7 @@
   <h3>Changes in this release</h3>
 
   <p>This release includes one new library
-  (<a href="libs/predef/index.html">Predef</a>),
+  (<a href="libs/align/">Align</a>),
   as well as updates to many existing libraries. See
   <a href="http://www.boost.org/users/history/version_1_56_0.html">Release
   History</a> for more information.</p>