[FIX] tools: html_sanitize: keep mako tags (<% ... %>), required for example in the portal sale quotation email.

manual fix of fp-style merge

[FIX] mail: compose wizard: fixed default_get overrides not correctly managing the received field_list + improved custom call to default_get to correctly manage its in and out values.

[FIX] crm: fixed day_open and day_close computation (conditional store + be sure that date_open and date_closed fields are set)

[FIX] project_issue, resource: fixed computation of hours / days to open (assign) or close an issue. Those fields now have a conditional store, because they were not recomputed even when changing date_open and date_closed. Changing the stage now correctly changes the date_closed. Also added some fixes in resource module, the date was not correctly taken into account when computing the number of working hours between two dates.

Due to the use of a sudo env, the records
were being added to the sudo cache one by
one instead of all at once. This meant the
prefetching was not able to load all
records at once, leading to prohibitive
times when processing thousands of
records.

+ correct tests

This avoids code duplication between methods, and keeps backward compatibility
with existing code overriding _name_search().

If a selection field is defined by a list as selection, such as:

    state = fields.Selection([('a', 'A'), ('b', 'B')])

one can extend it by inheritance by redefining the field, as:

    state = fields.Selection(selection_add=[('c', 'C')])

The result is that the selection field will have the list
[('a', 'A'), ('b', 'B'), ('c', 'C')] as selection.

As `_inherits` fields are now handled via `related`
fields (not stored, obviously), a new descriptor
`searchable` has been added to `fields_get()` result
to indicated if the field is searchable or not.

Added a record of im_livechat.channel in website_livechat data

Singleton object was required while access model properties, but search returns multiple results and hence caused traceback while accessing record.property

The one2many field 'user_ids' was initialized with an incorrect value for the
inverse field 'wizard_id', using a res.users id. The latter was causing a
MissingError exception. The fix is simply to not define explicitly the inverse
field in the one2many.

Also did a small cleanup of the code of the wizard.

(partial revert of 44a5268c)

The existing code was buggy when writing on *2many fields with a list of
commands: the value was converted for the cache, but taking an empty recordset
as the current value of the field.

[FIX] hr_contract: count the number of contracts of an employee as superuser_id as this field is required in the form view. However no data is displayed, and no data about the contracts are leaked, so no security holes.

Before, the field purchase_ok was set as readonly on the product form if the product wasn't a variant, to avoid users to set all the products variants associated to the product template to be set as purchase able in one action.

We now consider that this can be done by the end user

opw-611106, when clicking quickly Sales > Opportunities than Sales > Leads.

This makes the patching mechanism more flexible, and enables patching BaseModel,
for instance. This should fix #1501.

(rebase of #1534)

It is not useful to try to create foreign keys when the destination model is
a PostgreSQL view for example.
We already do this kind of verifications but ir.actions and transient models
but did not for _auto.

- simplify the code by removing unused cases
- do not modify input argument 'value' of create/write
- do not call BaseModel.read() with reified group fields (this causes warnings)

[FIX] point_of_sale: partner list rendering was not refreshing correctly. + limited display to 1000 partners for performance reasons

of switching back to default screen.

This is used by the soon to be merged restaurant addon to create new orders
and display them at a particular screen.  However, this behaviour is more
confusing in the other cases, so I'll think of a better way to solve this.

[IMP] pos_discount: a new pos extension that allows you to quickly give a global discount on the current order

[IMP] point_of_sale: made the server data loading more modular for easier development of point_of_sale extensions