Fixed day payment terms

[ced (Cédric Krier)]

@pokoli

If we have to declare it manually it can be easly solved by updating the term days manually once the invoice is posted .

Editing the line after posting should be a special case where the terms are re-negotiated afterward.
I still think we need to allow definition of custom terms manually.

@pokoli

Thanks for your effort but I do not think we should manage this case manually as we now that for each invoice

Of course, I do not say that this manual edition is a good solution when the term rules are perfectly known. But it will help for one time special case.

I’m still in favor of improving the current payment term design to filter out some lines with the current computed date.