NK_baseline_steadystate.m: add copyright notice

(cherry picked from commit c48542c3)

examples/NK_baseline_steadystate.m

@@ -15,6 +15,23 @@ function [ys,params,check] = NK_baseline_steadystate(ys,exo,M_,options_)
 %   - check     [scalar] set to 0 if steady state computation worked and to
 %                    1 of not (allows to impose restrictions on parameters)
 
+% Copyright (C) 2013-2020 Dynare Team
+%
+% This file is part of Dynare.
+%
+% Dynare is free software: you can redistribute it and/or modify
+% it under the terms of the GNU General Public License as published by
+% the Free Software Foundation, either version 3 of the License, or
+% (at your option) any later version.
+%
+% Dynare is distributed in the hope that it will be useful,
+% but WITHOUT ANY WARRANTY; without even the implied warranty of
+% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+% GNU General Public License for more details.
+%
+% You should have received a copy of the GNU General Public License
+% along with Dynare.  If not, see <http://www.gnu.org/licenses/>.
+
 % read out parameters to access them with their name
 NumberOfParameters = M_.param_nbr;
 for ii = 1:NumberOfParameters