Implement an ajax duplicate check when creating a new contact

Instead of having to click on check duplicates, the control can be done in the background:

you create a new individual, enters the first+last name, on blur, it runs an ajax search to see if there is an existing contact already. If it's the case, displays a warning message and offers to modify the existing one instead of creating a new contact.

cf. mepwatch presentation in London last year.