Bug 10798: make OPAC_SEARCH_LIMIT behaves better with search groups

Since the addition of search groups to Koha, the branch limiting
parameter in multiple PAC by URL support should also support
limiting by these search groups.  This patch adds this ability.

Signed-off-by: Srdjan <srdjan@catalyst.net.nz>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Bug 10798: (follow-up) replace tabs by spaces

Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>