Add sort_code field to res.bank
Add sort_code to bank form.
Rename res.partner.bank#sort_code to bank_sort_code, in line with
bank_bic etc
Move sort code field on res.partner.bank.form to just above the BIC
Add help tooltip to sort code fields.
Switched to v8 API for res_partner_bank_extension
Undo v8 API port, add sort code to auto-filled fields.