Rewrote overloaded vertcat method.

src/@dates/vertcat.m

-function B = vertcat(varargin)
+function o = vertcat(varargin)
     
 % Overloads the vertcat method for dates objects.
 %
 % INPUTS 
-%  o A1    dates object.
-%  o A2    dates object.
-%  o ...
+% - varargin [dates]
 %
 % OUTPUTS 
-%  o B    dates object containing dates defined in A1, A2, ...
+% - o [dates] object containing dates defined in varargin{:}
 %
 % EXAMPLE 1 
 %  If A, B and C are dates object the following syntax:
@@ -16,22 +14,24 @@ function B = vertcat(varargin)
 %    D = [A; B; C] ;
 %
 %  Defines a dates object D containing the dates appearing in A, B and C.
-    
-% Copyright (C) 2013 Dynare Team
-%
-% This file is part of Dynare.
+
+% Copyright (C) 2013-2014 Dynare Team
 %
-% Dynare is free software: you can redistribute it and/or modify
+% This code 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,
+% Dynare dates submodule 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/>.
-
-B = horzcat(varargin{:});
\ No newline at end of file
+    
+if ~all(cellfun(@isdates,varargin))
+    error('dates:vertcat:ArgCheck','All input arguments must be dates objects.')
+end
+    
+o = horzcat(varargin{:});
\ No newline at end of file