Fix of problem with ~p to format the benchmark parameters. ~p might
insert new-line characters in the formatted string which will cause a
corrupt output file. The new-line problem was solved by removing all
new-line characters (and white-spaces) after formatting with
~p. Another problem with ~p is that it will format lists of integers
as strings even if they are not intended to be a string. This was the
case for some of the benchmarks. This was solved by treating a
parameter list that just contains integers as a special case.