Work on the QWidget-autotest.

Work on the QWidget-autotest.

- Introduce smart pointers to delete widgets and resources
  to ensure tests are not affected by left-over widgets
  also in case of failure.
- Replace deprecated QTest::qWaitForWindowShown() by
  QTest::qWaitForWindowExposed() and use QVERIFY,
  remove some hard-coded timeouts.
- Set some titles and object names.
- Add verbose debug output of event lists in tests
  childEvents.
- Set minimum sizes on widgets to avoid Windows warnings.
- Stabilize GDIWidget, trigger on first event only.

Change-Id: I64119a2e7113e4a9f0156d00c72ce0935d03bb81
Reviewed-by: Joerg Bornemann <joerg.bornemann@nokia.com>