- Breaking up of the validation into two stages:
    - Performed by the importtransport object, before moving files
      around
    - Performed by the import class, after the files are transported

To this end I changed the importtransport objects to take the
importqueue record (or a fake one) in their constructor, so they have
the same data available as the importer would.

Signed-off-by: Penny Leach <penny@mjollnir.org>