Add new libraries to root index.html

index.html

@@ -55,7 +55,9 @@
 
   <h3>Changes in this release</h3>
 
-  <p>This release includes ??? new libraries (???),
+  <p>This release includes 2 new libraries (
+  <a href="libs/endian/index.html">Endian</a> and
+  <a href="libs/sort/index.html">Sort</a>),
   as well as updates to many existing libraries. See
   <a href="http://www.boost.org/users/history/version_1_58_0.html">Release
   History</a> for more information.</p>