QtAssistant: remove references to QApplication::Type
QtAssistant: remove references to QApplication::Type

Qt3 legacy QCoreApplication::Type and QApplication::type() will be
removed -> use qobject_cast instead.

Change-Id: I4a4af17ab6c8955af33779d1e5556610c443c93e
Reviewed-by: Friedemann Kleint <1b9f2592239daaec4856ccc1cfb4d2d55b35fb71@digia.com>
Reviewed-by: Samuel Rødal <99126055f8d73e4355b075213322026fa8c060bd@digia.com>

mer-qt/qttools,mer-qt/qttools,mer-qt/qttools,mer-qt/qttools,mer-qt/qttools,mer-qt/qttools