Bug 9257 - Add "groups" to normal search pulldown

Bug 9257 - Add "groups" to normal search pulldown

This patch adds the ability to add groups to the library select
pulldown on the opac, if it is enabled.

Test Plan:
1) Apply patch
2) Run updatedatabase.pl
3) Go to Administration › Libraries and groups
4) Create a new group, or edit an existing one
5) Ensure the 'Show in search pulldown' checkbox is checked
6) Save the group
7) Enable OpacAddMastheadLibraryPulldown if it is not already enabled
8) Load the OPAC, try the group search from the libraries pulldown menu

Signed-off-by: Liz Rea <liz@catalyst.net.nz>
Yes! Now this works, and well.

Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>