Bug 11869: (follow-up) only display active fines

Bug 11869: (follow-up) only display active fines

This patch modifies the patron summary printout so that
only fines with an outstanding balance (either positive
or negative) are displayed.  Also, the entire fines section
is displayed only if there is a non-zero balance.

This is consistent with the logic for displaying the loans
and hold requests tables, and avoids cluttering the summary
with historical fines.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>