Updating bankdetails to null and fetching an organisation's bank details.
1)Written code for updating bankdetails to NULL, when the user edits the paymentdetails (i.e. when the user switches to cash paymentmode from bank paymentmode) in api_invoice.
2)Written a getorgbankdetails() function in api_organisation to fetch organisations bankdetails.
please refer issue #854 (moved) at gkwebapp.