WUtil: Fixed incorrect header being included

WUtil's file misc.c was including the private header for WINGs, where it
should have been using WUtil's public header instead.

Took opportunity to include the appropriate copyright header.

Signed-off-by: Christophe CURIS <christophe.curis@free.fr>

WINGs/misc.c

@@ -1,7 +1,26 @@
+/* WUtil / misc.c
+ *
+ *  Copyright (c) 2001 Dan Pascu
+ *  Copyright (c) 2014 Window Maker Team
+ *
+ *  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.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
 
 /* Miscelaneous helper functions */
 
-#include "WINGsP.h"
+#include <WUtil.h>
 
 #include "error.h"