[FIX] tools,mail: improve parsing of references from rev. 0bee015dd67cb809fd235215b43d331074824e42

Backport of 8.0 fix was not enough for 7.0, because it still fails for the legacy reference match (model+res_id), which is not used in 8.0
[FIX] mail: translate tracked fields name in chatter

Status tracking messages are not translated into user's language while updating any document with tracked fields (opw 612847)
[FIX] web: do not allow to access a database if not matching db-filter
[FIX] stock: show the UoS quantity on picking lines

The pickings already show the UoS, but not the associated quantity, which makes it useless.
[IMP] css: width of readonly list view field

readonly float fields in list view were not correctly placed when the focus was on the line (seen espacially if field was large, e.g. nb_register on registration)
[FIX] ir_attachment: ignore if model uninstalled

if the model of an attachement no longer exists (the according module have been uninstalled, for instance), ignore the security check
[FIX] web: missing backport of rev df3c6b750249

[FIX] web: do not try to close a destroyed dialog. trigger "closing" signal on close by top-right "X" button
[FIX] hr_expense: tax included computation

When a tax included has a several childs, the source line should not be duplicated for each tax.
Without the patch, the actual product price (without taxes) would be (total - tax amount) for the last tax only (and not the sum of each tax). (opw 609104)
[FIX] orm, read_group: read_group_fill_results handle no_leaf
[MERGE] forward port of branch 7.0 up to 33e0910
[FIX] ir_qweb: contact widget: properly pass the context when browsing the contact

As the context was not transferred, it was never translated.
[MERGE] forward port of branch 7.0 up to 8dff247
[FIX] website_event_sale: take taxes from product_id_change into account
[FIX] email_template: a tag link rendering, do not process if no href
[FIX] web: stages positioned properly when there is no sheet

Fixes #271
Closes #2004
[FIX] ir_attachment: attachements removed on record unlink
[FIX] website_sale: The product breadcrumbs in shop not working. Internal Server Error appears
[FIX] point_of_sale: fix some image chaching issues with the receipt logo. Using a random url at each fetch ensures that we don't get cached results
[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