Don't crash if the QWindow's screen is temporarily invalid

It can happen during the transition between screens when one screen
is disconnected that the window doesn't have a screen.

Task-number: QTBUG-32681
Change-Id: I066855a2ffe80f0680a3044e73f4f491c2c0eb5c
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>
Mac Style: Fix 1-pixel text offset in combo box

Change-Id: Ie1bb2b300d6897659f4652c22884f1bd611cd3c4
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>
qobject: Do not destroy slot objects inside a lock

This prevents deadlocks in case the destructor re-enters.
(Example: a functor containing a QSharedPointer of a QObject)
This also fixes a leaked slot object in disconnectHelper.

Change-Id: Ia939790e3b54e64067b99540974306b4808a77f2
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Improve tst_QFileInfo::compare() test, but mark as QEXPECT_FAIL on Mac

As Qt still thinks that all UNIX filesystems are case sensitive, which
is not the case for eg Mac, where they might be both, as well as for
mounts of other filesystems.

Change-Id: I07b8550685bfa17ac407c20ac991dc54df040942
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>