allow several bank_accounts per company, refs #2559
allow to choose bank account on invoice form, on payment method dropdown. refs #2559
choose bank_info also with debit payments
Merge branch 'master' into multiple_bank_accounts
check project_id on n19_index
add permission to restrict who can add more than one bank_account
Merge branch 'master' into multiple_bank_accounts

Conflicts:
	app/controllers/companies_controller.rb
adapt client to multiple bank accounts
fix client form for linked clients
assign company bank_info to clients if its the only one
Merge branch 'multiple_bank_accounts'