Fix copyright character encoding in css.

Replaced ISO-8859-1 copyright character with (c) and changed the order
of date and name to be consistent with other copyrights.

doc/src/minimal.css

@@ -1,6 +1,6 @@
 /*
 
-  © Copyright Beman Dawes, 2007
+  Copyright (c) 2007 Beman Dawes
 
   Distributed under the Boost Software License, Version 1.0.
   See www.boost.org/LICENSE_1_0.txt