remove all .csv, shouldn't be mixing code and data

...except for a single representative sample of the expected and actual
output, you know, the stuff that unit-testing is all about. (TODO)
same
final output csv is command arg (appends)

Successfully append multiple input logs into a single output .csv
PROVIDED they all have matching columns. So *little.log is one set and
*-diff*.log is another. There is still some cleanup needed afterwards on
the Excel side: runs that were aborted early or had errors will have
different columns. They're easy to find and weed out.