add accumulators

[SVN r47012]

libs/libraries.htm

@@ -80,6 +80,8 @@ how to download, build, and install the libraries.</p>
 <h2>Libraries Listed <a name="Alphabetically">Alphabetically</a></h2>
 
 <ul>
+    <li><a href="accumulators/index.html">accumulators</a> - Framework for incremental
+        calculation, and collection of statistical accumulators, from Eric Niebler.</li>
     <li><a href="any/index.html">any</a> - Safe, generic container for single
       values of different value types, from Kevlin Henney.&nbsp;</li>
     <li><a href="array/index.html">array</a> - STL compliant
@@ -491,6 +493,8 @@ how to download, build, and install the libraries.</p>
 <h3><a name="Math">Math</a> and numerics</h3>
 
 <ul>
+    <li><a href="accumulators/index.html">accumulators</a> - Framework for incremental
+        calculation, and collection of statistical accumulators, from Eric Niebler.</li>
     <li><a href="integer/index.html">integer</a> - Headers to ease
         dealing with integral types.</li>
     <li><a href="numeric/interval/doc/interval.htm">interval </a>- Extends the