[FIX] im_chat, im_livechat : fix loading covnersation history and is_in_session function
[FIX] event: avoid double "Publish" button

The event.track view wa sextending the event.event view which was adding action buttons linked to the event.event object instead of the track.
This patch uses the general website view to avoid the confusion (and the risk of publishing an event instead a track).
[FIX] product: Put product_variant_count on template form view.

Was missing to be used in domain added at 92d8f15.
Fixes #2570
[FIX] Previous move subtleties
[IMP] Assign all destination moves at once, add packaging
Merge pull request #2603 from odoo-dev/8.0-wmsstaging10-jco

8.0 wmsstaging10 jco
[FIX] website_twitter: display setup/debug info only for website editors, not visitors
[IMP] crm: make code of merge opportunities overloadable
[FIX] models: only check existance of inverse_field for one2many fields
[IMP] mail: avoid sending an email twice

In some specific conditions (e.g. admin logging during cron run, concurrent update), writing on the mail object may fail, triggering a rollback of the transaction.
As the write was done after the SMTP sendmail action, an email could be sent twice (state not correctly put, would be retried at next process of the email queue).
This patch provoke the error before the sendmail action and thus avoids sending the email.
Fixes #552
[IMP] base: safer locking at user login

When a users connects, a lock is taken on the res_user table to modify the last login date. If another running transaction uses a foreign key to res.users (e.g. write_uid column), postgres may detect the update as a concurrent update and rollback the transaction.
In pg 9.3, the lock_strength parameter 'NO KEY' allows a weaker lock which is less likely to break another transaction.
Fixes #552
[FIX] bus: prevent error popups when longpolling requests are interrupted

1b9c404 modified the /longpolling/poll requests
to use openerp.session.rpc() instead of openerp.jsonRpc().
In order to properly disable error popups, an
explicit preventDefault() call is now required.