restored tab-delimited report download

restored tab-delimited report download

Previous patch broke this, always providing the
guided report download in CSV format regardless of
whether CSV or tab-delimited was requested.

Also, default name of downloaded file is reportresults.csv
for CSV output and reportresults.tab for tab-delimited.

Also removed a couple subroutine prototypes that
were leading to unnecessary compile-time warnings
under use warnings.

Signed-off-by: Galen Charlton <galen.charlton@liblime.com>
Signed-off-by: Henri-Damien LAURENT <henridamien.laurent@biblibre.com>