bug 6068, 6933. nsTableRowGroupFrame::CalculateRowHeights - changed row spans to consider
top and bottom margins during height calculations. Calculations using percentages ensure that the sum of
rows sum exactly to excess.
bug 6404 BasicTableLayoutStrategy::BalanceColumnsConstrained cols in span other than 1st col was
not getting additional allocations from cell. ::DistributeRemainSpace uses max width of col
instead of max effective width. Also added checks for negative value during percentage calculations.
git-svn-id: svn://10.0.0.236/trunk@32755 18797224-902f-48f8-a5cc-f745e15eee43
703e798b06