Update the copyright coredits -- Happy new year 2013!

llvm-svn: 171342
diff --git a/llvm/docs/doxygen.footer b/llvm/docs/doxygen.footer
index c492e7d..95d5434 100644
--- a/llvm/docs/doxygen.footer
+++ b/llvm/docs/doxygen.footer
@@ -3,7 +3,7 @@
 Generated on $datetime for <a href="http://llvm.org/">$projectname</a> by
 <a href="http://www.doxygen.org"><img src="doxygen.png" alt="Doxygen"
 align="middle" border="0"/>$doxygenversion</a><br>
-Copyright &copy; 2003-2012 University of Illinois at Urbana-Champaign.
+Copyright &copy; 2003-2013 University of Illinois at Urbana-Champaign.
 All Rights Reserved.</p>
 
 <hr>