Change license to wxWindows Library Licence

This is essentially the LGPL, with an exception stating that derived
works in binary form may be distributed on the user's own terms.
This is a solution that satisfies those who wish to produce GPL'ed
software using Frida, and also those producing proprietary software.

src/_frida.c

@@ -1,20 +1,7 @@
 /*
  * Copyright (C) 2013-2014 Ole André Vadla Ravnås <ole.andre.ravnas@tillitech.com>
  *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library 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
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
+ * Licence: wxWindows Library Licence, Version 3.1
  */
 
 #include <frida-core.h>