[IMP]hr_recruitment : Add a stat button for the created employee
[IMP] shell: load Odoo modules that have a "cli" directory
[IMP] config: allow defining addon_path in multiline

With a config like
[options]
addons_path: ~/foo,
	     ~/bar

'~/bar' was interprated as '\n    ~/bar' and is considered as a local directory
by os.path.abspath

Fixes #4403
[IMP] website_event_sale: validation of seats availability in cart.
Attendees are created and deleted on changing the quantity from the cart.

Added sale_order_id and sale_order_line_id fields on registrations, allowing
to find the order and the order line that created the registration without
to rely on origin and ticket.

Also fixed check_auto_confirmation, now in multi mode to avoid issues due to
the specific behavior of api.one.
[FIX] mass_mailing: updated link conversion.

Previously to this fix, url matching the same base url were linked to
the same shortened url: foo.be -> /aaa, foo.be/bar -> /aaa/bar instead of
a new shortened url.
[FIX]: envelop size in oe_systray
[FIX]: y-truncated username in usermenu
[IMP] Web: navbar isn't displayed on several lines while rendering

  - Add a new SystrayMenu widget to improve and facilitate the way
    of adding widgets in .oe_systray
  - Rendering of the modules menu now waits for the systray and
    user menus to be rendered