Improvements to --nstimes

[tgreenx]

From #421 (comments):

• The section mapping is defined once for the JSON output and once for table output. And the grand totals are calculated as part of the table output logic. IMHO it would be better to set up the data to be shown just once and do it before we branch to the individual output formats.
• Include "Grand total" in the JSON output
• Translate all headers, with dynamic table formatting
• Code styling suggestions (Expand --nstimes option #421 (review))