Fix date.

asio/src/doc/asio.qbk

diff --git a/asio/src/doc/asio.qbk b/asio/src/doc/asio.qbk
index 9abc6bb..3d3f565 100644
--- a/asio/src/doc/asio.qbk
+++ b/asio/src/doc/asio.qbk
@@ -7,7 +7,7 @@
 
 [library Asio
     [quickbook 1.4]
-    [copyright 2003 - 2011 Christopher M. Kohlhoff]
+    [copyright 2003 - 2012 Christopher M. Kohlhoff]
     [purpose Networking library]
     [license
         Distributed under the Boost Software License, Version 1.0.