Bug 12051: Adds a Renew tab to the staff client

Bug 12051: Adds a Renew tab to the staff client

UPDATE: Added to checkin-search.inc to show up on returns.pl

To test:

1) Apply patch
2) Confirm that there is now a Renew tab on the pages where there is also a Check-in tab only
3) Attempt to renew a book using this, confirm it works as expected
4) Check if I have missed any pages

Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Brendan Gallagher brendan@bywatersolutions.com