[IMP] allow many2many to specify formview (web client)

One2Many fields can specify sub tree and sub form view, to be used when
displaying a list view and when adding/editing an element.  Many2many
can display a sub tree view, but ignore sub formviews.  This can be
fixed by specifying an alternative_form_view to the popup form widget.
[IMP] account: account.statement.operation.template model
- better many2one ondelete strategies
- added analytic account domain
- added multi-company support
[IMP] im_livechat : the rule are now matching with the country (these are not blocked country anymore). A rule is define for a specific URL and country (if geoip installed). Add the sequence field to prioritize the matching. Also improve xml views.
[IMP] website_twitter: authentication error popup with proper description base on twitter error code and responses