Updated license headers

From Qt 5.7 -> tools & applications are lisenced under GPL v3 with some
exceptions, see
http://blog.qt.io/blog/2016/01/13/new-agreement-with-the-kde-free-qt-foundation/


Updated license headers to use new GPL-EXCEPT header instead of LGPL21 one
(in those files which will be under GPL 3 with exceptions)

Change-Id: I37338c968d8cb5a056cd42e1130cfa077b12d164
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>