Optimize QColor::setNamedColor

This patch removes two memory allocations from the algorithm.

Change-Id: I9366f9c5ce02fb1cae8adfbd8dff36c7f23af2a7
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
QWeakPointer: add lock() for std::weak_ptr compatibility

[ChangeLog][QtCore][QWeakPointer] Added lock() method for std::weak_ptr compatibility.

Change-Id: I0851d91c51f5a4f04a855a1d8082234ce38396b4
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
QWeakPointer: add member-swap

[ChangeLog][QtCore][QWeakPointer] Added member-swap function.

Change-Id: Ide3672dc74a9d8153e5f930290d938e8c23993b5
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Added handling of QT_LINUX_ACCESSIBILITY_ALWAYS_ON variable.

By setting this variable to non empty value we can, bypass
checking ScreenReaderEnabled proprty of org.a11y.Status
dbus interface. Not all accessibility readers set this.
The variable is also useful for debugging.

Change-Id: I6c5a1a51065948248e068dfff4755d6818ed9fb1
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@digia.com>