Update license file for 2013

(cherry picked from commit 7fe0e93e)

license.txt

 Format: http://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
 Upstream-Name: Dynare
-Upstream-Contact: Dynare Team, whose members in 2012 are:
+Upstream-Contact: Dynare Team, whose members in 2013 are:
                   Stéphane Adjemian <stephane.adjemian@univ-lemans.fr>
                   Houtan Bastani <houtan@dynare.org>
                   Michel Juillard <michel.juillard@mjui.fr>
@@ -14,7 +14,7 @@ Upstream-Contact: Dynare Team, whose members in 2012 are:
 Source: http://www.dynare.org
 
 Files: *
-Copyright: 1996-2012 Dynare Team
+Copyright: 1996-2013 Dynare Team
 License: GPL-3+
 
 Files: matlab/AIM/SP*
@@ -68,7 +68,7 @@ Copyright: 2008 Radek Salac
 License: GPL-3+
 
 Files: doc/dynare.texi doc/*.tex doc/*.svg doc/*.dia doc/*.pdf doc/*.bib
-Copyright: 1996-2012 Dynare Team
+Copyright: 1996-2013 Dynare Team
 License: GFDL-NIV-1.3+
 
 Files: doc/userguide/*.tex doc/userguide/*.bib doc/userguide/*.pdf