Prevent foolish use of setuid when using Qt.

In order to prevent people from shooting themselves in the foot, abort
if we're running setuid. This behavior can be disabled by calling
QCoreApplication::setSetuidAllowed(true) in order to support legacy code.

[ChangeLog][QtCore][Important Behavior Changes] Running Qt applications
that are setuid has been prevented. If you really need to do this then
you can call QCoreApplication::setSetuidAllowed(true) before creating the
QCoreApplication instance.

Change-Id: I992a9a0cd8420693d438852a05666e3dbb2c9d6a
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@digia.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Add takeTexture() to QOpenGLFramebufferObject

Add an API that allows to retrieve and detach the texture from the
framebuffer object. The next bind() call will then create and attach a
new texture.

[ChangeLog][QtGui][QOpenGLFramebufferObject] Added takeTexture() for
retrieving and detaching the texture from the framebuffer object.

Task-number: QTBUG-35881
Change-Id: I2cca37f5872c1685b1238047f8b912e6534ab781
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>