If a pipe table contains a line longer than the column
width (as set by `--columns` or 80 by default), relative
widths are computed based on the widths of the separator lines
relative to the column width.
This should solve persistent problems with long pipe tables in
LaTeX/PDF output, and give more flexibility for determining
relative column widths in other formats, too.
For narrower pipe tables, column widths of 0 are used,
telling pandoc not to specify widths explicitly in output
formats that permit this.
Closes#2471.
John MacFarlane
eb8aee477d
