Bug 6875 de-nesting Auth.pm

Bug 6875 de-nesting Auth.pm

* removed use C4::Koha that is useless
* moved "use C4::Members" to "require C4::Members" just before GetMemberDetails call. This will avoid loading C4::Member everytime a page is called by someone not logged

* still to do = work on C4::VirtualShelves, that can be optimized, definetly !

Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
Rebased on latest master, 28 Jan 2012

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Please WAIT with virtual shelves. Working on that..
Tested and marked as Passed QA.