Set default value for input argument, filter out files without an m

extension, and fixed the header.

src/get_directory_description.m

 function flist = get_directory_description(basedir)
 
-% Copyright (C) 2013 Dynare Team
+% List recursively all the *.m files in a directory.
 %
-% This file is part of Dynare.
+% INPUTS 
+%  - basedir [string], the name of the directory to be inspected.
+%
+% OUTPUTS 
+%  - flist   [cell of strings], the files under basedir (and subfolders).     
+
+% Copyright (C) 2013-2014 Dynare Team
+%
+% This file is part of Dynare (m-unit-tests module).
 %
 % 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.
+% Dynare's m-unit-tests module 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/>.
 
+if ~nargin || isempty(basedir)
+    % Current directory is the default value of basedir 
+    basedir = '.'; 
+end
+    
 dd = dir(basedir);
 flist = {};
 file = 1;
@@ -27,8 +40,11 @@ for f=1:length(dd)
             r = get_directory_description([ basedir filesep dd(f).name]);
             flist = { flist{:} r{:} };
         else
-            flist{length(flist)+1} = [basedir filesep dd(f).name];
+            % Filter out files without m extension.
+            if isequal(dd(f).name(end-1:end),'.m')
+                flist{length(flist)+1} = [basedir filesep dd(f).name];
+            end
         end
         file = file + 1; 
     end
-end
+end
\ No newline at end of file