* iap, web_tour This commit changes the API of the dialog service. Before, the API gave 2 functions: "open" and "close". Now, there is only one function "add" which is the same as "open" but returning a callback that does the close. closes odoo-dev/odoo#940 Related: odoo-dev/enterprise#171 Signed-off-by: Géry Debongnie (ged) <ged@openerp.com>