[IMP] event_sale: extra QWeb report for printing event badges, with HTML fields for custom content
[FIX] ir.attachment mess, restore list view
[FIX] website_mail_group: duplicate preventDefault() call (called before onclick already)

Plus it fails because `event` is not defined nor passed there (e.g. in Firefox)
[FIX] email_template: partners ids are integers, not strings
[MERGE] forward port of branch saas-3 up to revid faace84
[FIX] mail: view_mode "list" does not exists, it's "tree"
[MERGE] forward port of branch saas-4 up to revid c319dc4
[MERGE] forward port of branch saas-5 up to revid 587084f