Bug 10493: Add renewal script

Bug 10493: Add renewal script

This patch adds a renewal tool that functions similar to the returns where a
librarian can continuously scan items for renewal. This script blocks
renewals that are impossible, and allow the same renewal overrides
as circulation.pl

Test plan:
 1) Apply the patches for bug 8798
 2) Apply this patch
 3) Browse to /cgi-bin/koha/circ/renew.pl
 4) Enter an invalid barcode, you should get an error message
 5) Enter a valid, but not checked out barcode, you should get an error
    message.
 6) Enter a valid barcode that is checkout out and should be renewable,
    you should get a success message.
 7) Enable AllowRenewalLimitOverride
 8) Enter a barcode for an item that has been renewed too many times
 9) You should get a warning which you can override.
10) Disable AllowRenewalLimitOverride
11) Repeat steap 8
12) You should get a blocking error message
11) Enter a barcode for an item with unfilled holds on it,
    you should get an overridable warning

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
Passes all tests and QA script, some issues have been
addressed in follow-ups.

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