Port of Qt 4's Windows session management

This patch aims to implement the session management for Windows.
Based on the Qt 4 QApplication windows specific code

Task-number: QTBUG-28228
Task-number: QTBUG-33032
Change-Id: I7059298ad9661aebd51e77a03f55a7a04f461479
Reviewed-by: Kai Koehne <kai.koehne@digia.com>