Bug 7310: Code changes for Improving list permissions

Bug 7310: Code changes for Improving list permissions

This lays the foundation for further changes for report 7310.
Implements following points from the wiki page List permissions:
1) Preference that controls if users may create public lists in opac.
2) New add/delete own/delete other permissions per list.

Code has been changed (in some cases refactored). New permissions are not yet visible; with this patch current functionality is kept as much as possible while resolving several issues, improving permissions and extending the code for further developments (using the new permissions and sharing lists).

Feb 23, 2012 (revision): Changed defaults for new lists. Could also remove routine GetRecentShelves by using GetSomeShelfNames in catalogue/search.pl just as opac-search.pl already did. (More consistent.)

Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
Feb 29, 2012: Automerge version.
March 5, 2012: Rebase for pushed 4912 patch.
March 21, 2012: Rebased. Resolving some conflicts in relation to pushed report 7719.