Updated license headers and license tests

From Qt 5.7 -> tools & applications are licensed 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)

License header tests also updated to match current headers.

Change-Id: Ia6bdacaa3c5bbc9d31334e1a0cabfe502a484dc4
Reviewed-by: Jani Heikkinen <jani.heikkinen@qt.io>