add get_vendor_orders_uid to get all orders filtered by vendor uid
add correct action to form, which includes the view name @@orders. fix url parameter names and pass it over to next view, called via ajax. fix OrdersData query to allow filtering for customer and vendors.
add null selection to allow empty values
only include filters, if there are more than one items - first one is empty. change querystring building to use urllib.urlencode.