Bug 4906: Allow fine calculation to exclude grace period

Bug 4906: Allow fine calculation to exclude grace period

This patch adds the system preference FinesIncludeGracePeriod which
allows the library the choice to include the grace period when calculating
a fine ( Koha's current behavior ) or to ignore the grace period for
the purposes of fines calculation. It is set by default to preserve the
current behavior.

Signed-off-by: Srikanth Dhondi <srikanth@catalyst.net.nz>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Rebased March 8, 2013. Included renaming pref.
Works as advertised. Renamed the bug title and opened a new report for the
original bug.
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>