WebBasket: fix copying external items

* Fixes the copy of external items on basket
  created on the fly during the copy.

Reviewed-by: Tibor Simko <tibor.simko@cern.ch>
WebBasket: correct referer when adding to basket

* Fixes the handling of the referer when adding to basket and creating
  a new basket on the fly.  (closes #1194)

Reviewed-by: Tibor Simko <tibor.simko@cern.ch>