Separate --csv output of different lines

Change --csv behaviour again: Output one section per line, with all
values pertaining to this line immediately following the header.
Sections are separated by blank lines.

The previous way of first printing all headers, then all values made
it impossible to tell which values belong to which header.

Signed-off-by: Ulrich Klauer <ulrich@chirlu.de>
Add test for new --csv behaviour

Signed-off-by: Ulrich Klauer <ulrich@chirlu.de>
Remove spurious leading space

Output "[1]" instead of " [1]" in a --csv header.

Signed-off-by: Ulrich Klauer <ulrich@chirlu.de>
Warn if --trim-outliers is combined with --csv

Signed-off-by: Ulrich Klauer <ulrich@chirlu.de>
Use size_t consistently

Signed-off-by: Ulrich Klauer <ulrich@chirlu.de>
Add --suppress-invariant option

Don't show lines without varying numbers if --suppress-invariant is
given. Especially useful with --csv to avoid empty sections.

Signed-off-by: Ulrich Klauer <ulrich@chirlu.de>
Add test for --suppress-invariant

Signed-off-by: Ulrich Klauer <ulrich@chirlu.de>
Merge pull request #7 from uklauer/csv

CSV changes