[IMP] Show the button 'view delivery order' as soon as a picking exists
The button should appear no matter the state of the sale order, to be consistent with the rest of the application.
This makes it much faster for the sales person to find out about orders in shipping exceptions
[IMP] Show the button 'incomming shipment' as soon as an incoming picking exists
The button should appear no matter the state of the purchase order.
This makes it much faster for the purchase person to find out about orders in shipping exceptions
Merge pull request #25 from numerigraphe/7.0-ocb-delivery-button-states-on-so

[IMP] Show the button 'view delivery order' as soon as a picking exists, backport of https://github.com/odoo/odoo/commit/57ad75b08d1bce1b1f1d0694c3dcda7368316a60