[IMP] website_forum: add a new karma to control the
way links displayed in posts and answers. A nofollow attribute is
added is the author has not enough karma, adding a protection for
spammer tryign to improve their SEO.
[IMP] productbetter menutips and help for product menus.
[FIX] event: fixed call to _check_auto_confirmation
done as api.one -> take first item in result list.

A test has been added; registrations were always automatically confirmed
even when auto_confirmation parameter was False.
[IMP] website_event_sale:  'Validation of seats availability in cart'.
Attendees are created and deleted on changing the quantity from the cart.
[WIP] Fucking tour.