QQuickFramebufferObject is flipped on Y axis in QML

We should allow flipping the y coordinate more easily in the QQuickFramebufferObject class, see https://bugreports.qt-project.org/browse/QTBUG-41073 A QML way to do the same would be to set a transform: Scale { xScale: 1; yScale: -1; origin.x: width / 2; origin.y: height / 2; }. Basically flip the way it is rendered to screen. Be aware of that this will also flip input events though, so if you have a MouseArea or similar you will have to place it besides the FBO or take the inversion into account.