[FIX] models: in method onchange(), check for record dirtiness only on *2many fiels

Cascading onchanges can be caused by a related field computed in cache.  This
causes a bug in sale order lines, were setting the uom field forces reading
product fields, which are inherited from product templates.  The inherited
fields are computed as related fields, which marks the product record as dirty.
This subsequently triggers an onchange on the product field, which resets the
uom field!
[FIX] point_of_sale: chrome was dropping the cookie when loading the company logo, resulting in an incorrect logo in multi-db setups.
[FIX] mrp: force empty values for fields that were dropped

This ensures the field values are cleared during
upgrades from previous versions
[FIX] product,purchase,point_of_sale: force empty values for dropped fields

At 96f038a product-related fields were removed due
to an important product.template/product.product
refactoring. As the field values were simply
dropped, they may not be nullified when upgrading an
existing database. Forcing them to False will take
care of it.
[FIX] hr_recruitment: fixed computation and storage of day_open and day_close + assignment of date_open and date_closed.
[FIX] sale: force default values for dropped fields

Those values were dropped at rev 3b636a5 but
need to be forced back to default so older
databases get properly updated when upgrading.
[FIX] mrp: force default values for dropped fields

Those values were dropped at rev 9b34358 but
need to be forced to empty so older databases
get fixed when upgrading
[FIX] website_event_track: force type from related to fix bug with convert_to_cache on picture
[FIX] website_blog: wait that document is ready before to check if we need to update menu for blog
[FIX] website_blog: change group restriction to load the JS editor
[FIX] website_blog: fix js error from 0a8aad990c86b18dfba5bb5dc964847fd97e7153
[IMP] point_of_sale: field company_id on pos.config view

Move invisible field on bottom to avoid blank space in view if display journal, group or sequence field
[FIX] models: in onchange(), do not send a field value if it has not changed

The method onchange() executes onchange methods in cascade.  Suppose onchange()
is called and a field F=1 in the form.  If an onchange method set F=2, that
value is put in the result variable.  If another onchange method set it back to
F=1, the binding F=2 must be removed from the result variable.

Fixes #2309
[FIX] web: modals: overflow-x on modal-body to prevent large content to be displayed outside
[FIX] web: about odoo: correct bootstrap structure inside the modal

Bootstrap's container class has a fixed width, using it in a modal
with the previous commit allowing an horizontal scrollbar makes the
layout goes crazy. Use container-fluid instead and cleaned some css.
[FIX] website_forum: header template: double display of questions

The <t t-raw='0'/> is already defined lower in the view (line 101)
[FIX] fields: in computed fields, handle AccessError and MissingError

When computing a field on a recordset, a subset of the records may be missing
or forbidden by access rules.  In that case, evaluate the compute method record
by record, and mark failed records as such in cache.
[FIX] web: scroll should move top on clicking menu on top bar

Backported from 97d99d1974c965506ed9005d4854fcc5ffee0590
[IMP] website_blog: more generic xpath expression when inheriting view. ease migration.
[FIX] stock: multicompany warehouse creation

When creating a new warehouse, the linked locations should have the same company as the warehouse.
The company_id field is required on warehouse (not necessary in vals as could be added by default values) while it is not for stock.location (meaning global location, also filled with default value).