Base class for box containers. Arranges child [Control] nodes vertically or horizontally, and rearranges them automatically when their minimum size changes. Adds a [Control] node to the box as a spacer. If [code]begin[/code] is [code]true[/code], it will insert the [Control] node in front of all other children. The alignment of the container's children (must be one of [constant ALIGN_BEGIN], [constant ALIGN_CENTER], or [constant ALIGN_END]). Aligns children with the beginning of the container. Aligns children with the center of the container. Aligns children with the end of the container.