Add Window.SetBounds to set a window's position and size in a single call

Desktop apps that manage window geometry in code — custom-drawn UI frameworks, custom resize behaviour, or re-anchoring a window while it changes size — currently have to assign Left, Top, Width, and Height separately. Each assignment is applied to the operating system window separately, so a combined move-and-resize briefly passes through intermediate states and the window visibly bounces or jitters, especially on Windows.

Add a Window.SetBounds(Left As Integer, Top As Integer, Width As Integer, Height As Integer) method that applies all four values in a single update, so the window moves and resizes in one visual step with no intermediate states.

Requested by a user building a custom UI framework on top of Objo who reports visible jitter when their framework resizes windows.