Merge of following commits from Trunk:
r32609: * GroupDAV preference for addressbook-home-set (requires to register hooks)
r32610: missing groupdav hooks
r32611: fixed missing "users" of principal url in calendar-user-address-set
r32615: as the pricipal of current user is influenced by GroupDAV prefs, we have to include them in the etag
r32619: loop over existing addressbooks, to make sure each ab is only once in addressbook-home-set, even when selected multiple times in the prefs because of symbolic ab like "primary group"
r32620: urlencode and decode account_lid in url to cope with group-names with space in it, which stall iPhone OS 4.2 devices
r32621: fixed bug: GroupDAV/CardDAV PUT request to /addressbook/ changes owner, also checking now required ACL for moving contacts between addressbooks
r32622: returning "403 Forbidden" if addressbook_bo->save() fails, happens when writing new entries in ABs without ADD rights
r32623: * iCal on iPhone detects URL now correct
reverted calendar-home-set to report only users calendar, as reporting multiple break propfind
r32624: we need a real redirect, not just a proxy
r32631: fixed working in GroupDAV prefs and translation
- register_all_hooks deletes now hooks of no longer existing apps
- hooks get instanciated directly with egw object, to cache the hooks
read from the DB (and not read it again on each request)
- hooks get now stored by location, so no need anymore too loop for each
hooks::process() call to all apps to find applying hooks
- hooks::process($location,$order,$no_permission_check) no longer
defaults automatically puts current app in $order, if $order is not
given, without $order hooks are executed in application order!
- allows to parse arguments ot the hook and return content
- all access to the hook-table is now handled by the hook-class (for admin and setup too)
- all existing hooks continue to work of cause
