Bug 10599: add option to unselect on loan items on the batch item modification tool

Bug 10599: add option to unselect on loan items on the batch item modification tool

Sometimes when using the batch item modification tool, we would like to
automatically uncheck on loan items.

This patch also adds a new routine in C4::Circulation, IsItemIssued(),
which, when passed an itemnumber, returns whether the item is
currently on loan.

Test plan:
1/ Go to tools/batchMod.pl.
2/ Enter some barcode (at least 1 should be on loan).
3/ Click on the Continue button.
4/ Click on the "Clear on loan" link.
5/ Check that on loan items are unchecked.

Launch the unit test file:
prove t/db_dependent/Circulation/IsItemIssued.t

http://bugs.koha-community.org/show_bug.cgi?id=10572
Signed-off-by: Liz Rea <liz@catalyst.net.nz>
Works as expected, only modifies items that are checked (still). No regression noted.

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Passes koha-qa.pl, works as advertised.

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