Fix Box size calculation issue

When calculating the size of a Box, allow returning a size bigger that the
provided constraint if the box doesn't fit the constraint. This is required
for example when calculating the preferred size of a window when it already
has a specific width and height.
[WPF] Box sizing optimization

Only recalculate the desired size of children when its location changes.
Don't do it on ArrangeOverride since it may enter on an infinite loop
of arrangements.
[WPF] Paned sizing improvements

Don't constraint the height of panels in horizontal layouts
(and width on vertical layouts)
[WPF] Changed the way window size is calculated
More Window size calculation fixes

Subtract the size of the decorations from the available size used to
calculate the preferred size of the root widget.