Fixes some of access rights issues. This addons branch features : - message_is_follower field added in invisible in all views using Chatter - update of message_follower_ids, to use message_is_follower, and to properly handle users not having access to the res.partner model (ex: basic portal users, anonymous users) - misc access rights tuning bzr revid: abo@openerp.com-20120928173655-uh9rzio2zpl8vfpx