[IMP] account/sale/sale_layout: standardization of Quotation/Sale Order/Invoice printed layout + add missing information

- Column alignment and order are now uniform across those reports.
- Display Due date on invoices.
- Display payment term and fiscal positions notes.
[IMP] graph view on contacts
[FIX] sell future events only, not old ones
[MIG]migrate to new api

[IMP]remove unneccessary stuff

[IMP]remove dead code

[IMP]improve the ranking function and some code

[IMP]rename the moethod _postproces_content ro _postprocess_content and improve the mail message disucssion method