show the table headers if --tsv is used

I want to store maxctrl output (mostly statistics) in a log file. The color codes and utf-8 borders of the default tabular output are shown as garbage if the log file is displayed. Therefor I use the --tsv option to display the tables as tab separated test. But: option --tsv does not display the table headers.

This ticket is about adding table headers in maxctrl output (and maybe elsewhere, where it applies too) when --tsv is used.