[FIX] sale: rounded sales team invoiced gauge

The price_total field of the account invoice report is not rounded (it cannot be easily rounded, as this has to be done in the sql view)
In a multi currencies environment, this is possible that the price_total value has a lot of digits
We therefore round it manually, for the gauge of the sales team kanban view
[FIX] Use _unknown model for missing models in relation fields

During a migration of database, it is possible that some custom field
("x_", state is 'manual') are relational to model from a module that is
not provided.

Note: this used to work in Odoo 7.0 but crashed in 8.0.

Closes #3877
[FIX] purchase: remove redundancy in report

The warehouse name and address name is often the same (name of the company).
Remove the name of the address as two warehouse may use the same address.
Fixes #4062
[FIX] sale_stock: product_id_change_with_wh on sale order popup too

product_id_change_with_wh onchange was not anymore called when using the popup form in sale order line.

The behavior was different concerning the product onchange when being in the editable list or in the popup form
For instance, for make to stock products not having enough stock, the warning was displayed when being in editable list, but not in the popup form

This is a regression of rev. 86f785ae1b2741ab67384f3022b971ab638daeb8

opw-619624
[FIX] purchase: replace company_id widget selection by option no_create

For selection fields, name_get calls to resolve the display name are client-side initiated, and will display "Unknown" if the user does not have read access to the selected company. And the reason for using a selection widget in the first place was to prevent inadvertent creation of companies. This is now doable via the no_create option, so we can remove the selection widget.
[FIX] account: 'currency_id' field not defined on account.bank.statement object (correct name is 'currency')
[FIX] web: get conditional user defaults

This is possible to set field conditional defaults, if the field has the attribute "change_default".
The defaults are set by the web client, by calling the method "get_defaults" of ir.values model, when the onchange is triggered on the field on which the condition is.

In 7.0, all onchanges were triggered clientside, one by one. On creation, the defaults of default_get method were pushed in the form, and then, as the values of the fields were changed (from null to the default value), all onchanges on which there was default value were triggered.

In 8.0, onchanges are performed server side, all at once. On creation, the onchange method is triggered by default (wether or not there is a default value for them), for all fields (widget param of method do_onchange of view_forms js is undefined, meaning the onchange is not triggered on a specific field, but on all fields). In such a case, we must call the get_defaults method of ir.values model for all fields (having change_default attribute), in order the conditional defaults to be set in the form view.
[FIX] purchase: replace widget selection by option no_create

For the same reasons as 37c805f26f7a536dc16b6427ba1cd0abbfce85bd
[FIX] ensure default addon paths are valid (existing)

User-provided addons paths are checked for existence (and rejected), but
default addons paths are not checked, and blow up when trying to listdir
them (e.g. when http.py tries to load modules).

This is an issue when using Odoo from the distributed tarballs, because
the packaging currently moves all modules to openerp/addons and removes
the root ("main") addons directory.