QLCDNumber: remove unused header #include

Change-Id: Ic1608a11a48c373b7ad816c1305cce0fe236425b
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
added QAbstractSpinBox::setGroupSeparatorShown function.

[ChangeLog][QtWidgets][QAbstractSpinBox] QTBUG-5142 - This will
allow a group (thousand) separator to be shown in QSpinBox
and QDoubleSpinBox widgets.

Task-number: QTBUG-5142

Change-Id: I2e23f5f83c93bb092a2dbd784e06d17d40d42909
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Doc: update the documentation of QStandardPaths to be more thorough

Specifically, note what paths can be empty and which ones can't (modulo
system mis-configuration, like an empty $HOME var) and describe what
implications there are for application-specific paths and for global
(user) paths.

Change-Id: If6c11aab466ba50f3a9685dce52dd51b86426f27
Reviewed-by: David Faure <david.faure@kdab.com>