When moving a window, we will now move any child windows by the same
position delta as the parent. This makes ComboBox popup list windows
follow the window they were opened by, which looks nice. :^)
If a window has another window in its Core::Object ancestor chain,
we now communicate that relationship to WindowServer so that it can
act with awareness of parent/child windows.
Previously windows would either extend past the screen or stay at their
previous smaller size in the corner, now they are resized to fit the new
resolution.
We were not repainting windows that were occluded at the time of the
theme changing. This patch adds a way to bypass occlusion testing when
invalidating window rects.
Fixes#1249.
