Base class for flow containers. Arranges child [Control] nodes vertically or horizontally in a left-to-right or top-to-bottom flow. A line is filled with [Control] nodes until no more fit on the same line, similar to text in an autowrapped label. Returns the current line count. If [code]true[/code], the [FlowContainer] will arrange its children vertically, rather than horizontally. Can't be changed when using [HFlowContainer] and [VFlowContainer]. The horizontal separation of children nodes. The vertical separation of children nodes.