Made sure GPL notice was included in all other source files.

src/sounds.h

@@ -4,11 +4,26 @@
   For Tux Paint
   List of sound effects.
 
-  Copyright (c) 2005 by Bill Kendrick
+  Copyright (c) 2002-2006 by Bill Kendrick and others
   bill@newbreedsoftware.com
   http://www.newbreedsoftware.com/tuxpaint/
 
-  June 15, 2002 - July 17, 2005
+  This program 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 2 of the License, or
+  (at your option) any later version.
+
+  This program 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 this program; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+  (See COPYING.txt)
+
+  June 15, 2002 - February 12, 2006
   $Id$
 */