QmlDesigner: Always reset the items in the render loop

To be sure the are not any more dirty. This can be no harm.

Change-Id: I861243f1f4435b0dbdc2a6373ebfdfef12fb2627
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>
QmlDesigner: Fix rendering rendering of items

The else clause was wrong. It should be that it is not a node instance but
it was that it was not a dirty node instance.

Change-Id: I657bbc03826edcb9a1ea46f9c3b44404b2d3f31a
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>
QmlDesigner: Remove harmful updates

From the quick1 times we always have done a update but it is not any more
useful and it is triggering a repaint which makes the form editor sluggish.

Change-Id: I8103d03c295aa73e14b4b4fcec15b01069c62754
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>
QmlDesigner: Fix spelling

Change-Id: Ifc17bab623b8e227b7511016f3f31db4edb77fe4
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>