bug 2991: Request hold on multiple items at one time.

bug 2991: Request hold on multiple items at one time.

Updated the results, cart, and shelf pages to include a button
or link to initiate a hold request based on checked items.

Updated the request CGI scripts to handle multiple biblio items.

Updated the reserve confirmation page to display multiple items,
with an optional list of copies for each one.

Turned on warnings in opac/opac-reserve.pl and fixed resulting
warnings.

Signed-off-by: Galen Charlton <galen.charlton@liblime.com>