Bug 20436: Add ability to specify itemtypes for longoverdue.pl

Bug 20436: Add ability to specify itemtypes for longoverdue.pl

It would be nice if we could filter long overdues based on itemtype the same way we can already filter based on borrower category code.

Test Plan:
1) Set up a number of overdues of various itemtypes
2) Run longoverdue.pl with --list-itemtypes to show itemtypes
3) Run longoverdue.pl with --itemtype to verify it only operates on that itemtype
4) Run longoverdue.pl with multiple --itemtype switches, verify it only operates on those itemtypes
5) Run longoverdue.pl with --skip-itemtype to verify it does not operate on that itemtype
6) Run longoverdue.pl with multiple --skip-itemtype switches, verify that it does not operate on those itemtypes

Signed-off-by: Jesse Maseto <jesse@bywatersolution.com>
Signed-off-by: Liz Rea <wizzyrea@gmail.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>