[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] 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
[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
[IMP] openerp.api: improve documentation
[FIX] im_char: correct display over kanban view
[FIX] gamification: prevent traceback in goals history

Closes #1536
[FIX] procurement: missing variable

scheduler_cron_id was not initialised so the scheduler always crashed (with just info message)
[FIX] mrp: duplicated find bom buttons

The product_id field is not required on a mrp.bom (while product_tmpl_id is). When searching for BOMs linked to a product.product, we should display the one specific to this product and the ones linked to the template (but not linked to another variant).
[REF] mail: same_thread field changed into no_auto_thread, its contrary, to avoid migration issues (adding a 'always False' column is easier than an 'always True').