Merge from nse back-end partial picking wizard
[FIX] better responsibilities on objects POS
[FIX] recursion
[FIX] difference POS / Cash
[IMP] readable code
[FIX] web: fixed css of hidden input file: a hidden element could interfere with other elements
in the dom, leading to some fields not being accessible.
[FIX] ir_actions: server action: check the validity of write_expresison only if defined. Also check for the related model only if set in the onchange.
[FIX] ir_actions: server action: when creating or writing value on a record
through a server action, try to correctly set the value to write on a given
fields according to its type. For example many2one fields should receive an
int, not a unique containing the id of the new value.
* [8.0][mass_mailing] some fixes
* [FIX] rename wrong mailing_type field and add missing fields when creating a mass mailing from the composer
* [FIX] coerce tooltip to an unicode string to avoid a json crash when locale produces a non unicode string for strftime(%B)
* [FIX] repair wrong sql statement computing statistics
[IMP] Graph views: show always measure + filters record measures in context
[FIX] point_of_sale: report, product_id of line is product_product

product_id column of pos_order_line is a product_product
the left join of l.product_id was done on product_template, instead of product_product

It worked as long as the ids product_product were the same as product_template. Meaning that, if you used variants, this report view was screwed.
[IMP] board: do not filter actions anymore

Starting from v8.0, there's only "My Dashboard". We can assume that we
have access rights to all the actions we pin to our proper dashboard, so
we can remove this filtering. Furthermore, this was a large performance
pitfall.
[IMP] Usability improvements by clarifying texts
[IMP] account_budget: added date filter in print budget report

Fixes #1743, opw 611307
[IMP] lazy loading of dashboards

The widget AddToDashboard used to make an ajax call every time the
search view is loaded.  This is often useless and can be annoying when
that request is long.  With this patch, the request is only done when
the user click on the widget AddToDashboard
[IMP] point_of_sale: add missing functionality necessary for the loyalty module
[FIX] fields: add missing option 'sanitize' on Html fields
Merge pull request #1888 from odoo-dev/8.0-wmsnsewiz-jco

Merge from nse back-end partial picking wizard
[FIX] base: wrong model change check

Comparing an id and a browse record will always fail so the exception would have always been raised when changing a model (e.g. updating a module with custom fields).
[FIX] note: small bugs