Reorient the share generation Tables

[roconnor-blockstream]

When creating shares using the tables, usually one is writing out the multiple shares at the same time on scratch paper in multiple rows. Therefore it might be easier to transcribe from the table if the shares are written vertically instead of the current horizontal layout. That way you copy a column from the table to a column on your scratch paper.

The disadvantage is that columns are somewhat harder to read. Adding striped column background would help guide one's eyes.