[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
[MERGE] forward port of branch 7.0 up to cb91966
[MERGE] forward port of branch saas-3 up to 48ffbb6
[FIX] base: incorrect code and locale for Bosnian

Stems from prebiblical commit f083aa2.

Fixes #3480
[IMP] *: one Makefile to rules them all.

Create one unique generic Makefile to compile sass files.
[MERGE] forward port of branch 7.0 up to 65d92da
[FIX] point_of_sale: the order should not be displayed in the print screen, and the order should not reprint itself automatically after the first time we go on the print screen
[MERGE] forward port of branch saas-3 up to d36eee9
[FIX] web,web_kanban: correct radial-gradient usage