[MERGE] Merged OpenChatter part 5.1: Mailbox Gangnam Style, A Reborn Bourriquet

Fixes and improvements :
- posting on the Wall now post on res.users with correct uid
- posting on res.users redirect on the related partner, when using message_post_api
- default subtype is False, not comment, otherwise you will be spammed with all logs produced by internal notifications
- removed the 'is_private' field; a private message is a message without model and res_id
- (un)read on mail.message is now to_read, based on the notification; when setting as (un)read messages for which you do not have a notification (i.e. parents added for threading), notifications are automatically created and set as (un)read; web client does not have to care about having notifications, juste set (un)read
- email_template: templates added in menu actions now correctly use the template by adding the default_use_template key in context
- mail_followers widget: fixed the behavior; fixed subtypes displayed only when following the document; improved the generic display when not being able to read on res.partner; overall code cleaning in subtypes
- various small fixes
Access rules/rights :
- message_read and its child methods now use read instead of browse, because of access issues due to the prefetching and ids cache
- various fixes related to access rights
Tests :
- updated and cleaned the needaction tests
- access rights tests are uncommented; it seems weird to comment tests that crash instead of trying to resolve the crash, but, well, they are back
Cleaning :
- mail.compose.message: removed Chatter form view
- various cleaning in mail

bzr revid: tde@openerp.com-20121018102601-bwtcd897wmr3fwg0