[FIX] mass_mailing: possibility to subscribe again to a mailing list

It was not possible to subscribe again to a mailing list once unsubscribed
[FIX] website_sale: confirm sale order on payment_confirmation

Same behavior than in saas-5
[FIX] web: multiple opened modal need fixing since bootstrap lib update
[FIX] website: slug: fallback to positive ID when slug appears to contain a missing negative ID

In some rare cases database records have negative IDs,
so the slug URL could look like /foo--20. This could
be mistaken for a slug ending with a `-` and a positive ID.
The latter is not supposed to happned as final hyphens
are stripped by slugify, but has been used in the past
and may be used in old links.
[FIX] website: update url in the footer
[FIX] orm: set default before removing magic fields

When a record is created, the magic fields (id, create_date,...) are first removed from the vals as the user should not set a value for these.
However if a value for this is given in default value (e.g. defined in an ir.value), the creation would crash (sql error : column specified more than once) as the magic column would be added again.
[FIX] product_visible_discount: multicurrency pricelists

When we compute the discount of a product to display (result of product_id_change), we compare prices in the currency of the product while we expect prices in the currency of the pricelist. opw 606188
[FIX] calendar: onchange_dates: protect against void dates (for example when creating a meeting through the form view)
[IMP] base: show possible titles for companies (opw 608243)
[FIX] account: res.partner: limit access to "total_invoiced" field to group "group_account_invoice". Use SUPERUSER_ID to access data
[FIX] Model.load(): extra error checking while importing data

If any missing or partially incorrect values cause
an exception other than a psycopg2 error, we should
still catch it, rollback that record and report
the error, rather than letting bubble and fail
without any feedback to the user.

Fixes #1485
[MERGE] Forward-port 7.0 up to 9411a2da
[FIX] website: OpenERP->Odoo in website footer
[MERGE] Forward-port saas-3 up to fc92027
[MERGE] Forward-port saas-3 up to 7273474
[FIX] product_visible_discount: no crash when no pricelist passed or product without company

Fixes an error introduced in f6fb2b6
[MERGE] Forward-port saas-5 up to 37ba23d
[MERGE] Forward-port 8.0 up to d706adb
[MOVE] account: moved account/project files to analytic or account, depending on which module the moved code belongs to. This allows to remove references to project in account module. Also added some improvements in project when deleting a project (delete account if void) or when deleting an account (delete project if void).
[FIX] web: warn of possible data loss when click on Odoo logo