"widthIncludesScrollbar" parameter to handle scrollbar inside the container

[phts]

I think it would good to determine whether a scrollbar width should be included into width parameter or not.

widthIncludesScrollbar == true means the scrollbar will not widen a wrapper and the wrapper will always have specified width by the parameter. The wrapper will contain table element of (width minus scrollbar width) width. The header will be of width width.

Also works if width is null.