CellData keeps track of row versus col spans.
nsColFrame keeps track of what cell contributed to constrained width.
nsCellMap::GetCellFrameAt replace with GetCellInfoAt
simplified nsTableCellFrame::RecalcLayoutData and removed FindLargestMargin, CalculateMargins, CalculateMargins
simplified nsTableFrame::RecalcLayoutData and removed AppendLayoutData
Added gsDebugReflow capability, remove all existing debug printf