Improve signal invocation performance, from Robert Zeh

[SVN r35432]

index.htm

@@ -257,7 +257,7 @@
                           Library</a>:</span> Boost.Function now implements a
                           small buffer optimization, which can drastically
                           improve the performance when copying or
-                          construction Boost.Function objects storing small
+                          constructing Boost.Function objects storing small
                           function objects. For instance,
                           <code>bind(&amp;X:foo, &amp;x, _1, _2)</code>
                           requires no heap allocation when placed into a
@@ -454,6 +454,11 @@
                             </ul>
                           </li>
 
+                      <li><span class="library"><a href=
+                      "../doc/html/signals.html">Signals Library</a>:</span>
+                      More improvements to signal invocation performance from
+                      Robert Zeh.</li>
+
                           <li>
                             <span class="library"><a href=
                             "libs/smart_ptr/smart_ptr.htm">Smart