[FIX] Report: get_pdf:  don't miss main elements when parsing html

Main elements can have more than one class, thus can be ignored by the previous
naive xpath. This patch brings a stronger xpath.
[FIX] product: pricelists based on the supplier prices now return first supplier price if partner not in suppliers instead of returning 0

Without this, sale pricelists cannot be based on supplier prices as the partner is never a supplier so the price would be 0
Note: behavior change ok with fp
[FIX] mrp: chain product move and MO locations

When validating a SO containing a `make to stock` + `manufacture` product
(with bom + orderpoint), we have the following stock moves:
* Product move
* Manufacturing order
Selling 1 such product would yield 2 as incoming quantity, an
inconsistency that this commit solves by setting the location_id of the
product move to the MO's location_dest_id (in the same fashion that
the create_pickings method does in an mts/buy case)

opw-616229
[FIX] ir_qweb: contact widget: use name_get instead of display_name

display_name field is overidden in res.partner in order to pop the context
key leading to show the address, and we want the address.
[FIX] web: inhibit on change flag when validating editable list

To valid all editable list line, we iterate on the lines and set the editor form with the line value, using set_value.
The _inhibit_on_change_flag should be set to True to avoid triggering on changes events

opw-617395
[MERGE] forward port of branch 7.0 up to cd69dee
[MERGE] forward port of branch saas-3 up to c666030
Revert "[FIX] mrp: chain product move and MO locations"

This reverts commit 61a8971db510dbb0e087bba09858fe8b94c7b16d.

This rev. is from a 7.0 forward port b4d602fdd3379a0310ec0b9a56f9b88226

This is no longer needed in 8.0, with the new WMS
[IMP] account: (over)due payments report

The report includes all due payments, not only the one after the maturity date.
The maturity date is displayed in the report so no confusion is possible for payments below the maturity date.
Fixes #3064
[IMP] doc: various improvements to website tutorial

closes #3476
closes #3477
closes #3479
[FIX] account_asset: move lines should use the depreciation line date

opw-616843
[FIX] forum: closing spam/offensive questions should give author karma penalty

This is a partial patch for issue #3460, pending more
improvements and refinements in master.

Currently the karma penalty is hardcoded to 5*downvote penalty,
which may or may not be sufficient to prevent posting, depending
on the other karma levels.
[FIX] longpolling/gevent: log errors occurring in main loop
[FIX] longpolling/gevent: automatically restart worker when killed

Whenever the longpolling/gevent worker dies, it
should be automatically restarted by the prefork
server, just like it happens for HTTP workers.
[FIX] doc: typo missed when merging contribution
[IMP] safe_eval allow math
[FIX] account_asset: asset depreciation should use the correct dates

fix a5cf71973916f3e9b6ea578a614c76b0b34689d8
[IMP] sale_order_dates: quotation views (backport of b5e9e11)

Add the same fields on the quotation tree view than on the sale order tree view.
[FIX] website: correct padding of footer
[REVERT] 056c06570c741fab1515978a957766b0a77bd80a and a5cf71973916f3e9b6ea578a614c76b0b34689d8