exception_ptr improvements, documentation update.

[SVN r52981]

doc/source/html_prefix.txt

@@ -12,7 +12,7 @@
 <div class="body-2">
 <div>
 <div id="boost_logo">
-<a href="http://www.boost.org"><img style="border:0" src="http://www.boost.org/boost.png" alt="Boost" width="277" height="86"/></a>
+<a href="http://www.boost.org"><img style="border:0" src="../../../boost.png" alt="Boost" width="277" height="86"/></a>
 </div>
 <h1>Boost Exception</h1>
 </div>