Adding 2 options to prep_ebook_records.py script

Adding 2 options to prep_ebook_records.py script

This supports 2 additional options to Dan Scott's ebook script:

    -t / --tcn : The name of the file to route TCN duplicates to.

The tcn search takes the 001 and does an OpenSRF open-ils.search.biblio.tcn
call.

   -u / --url : The name of the file to route URL duplicates to.

The url search is based on the 856u field and is done with the OpenSRF
open-ils.search.biblio.multiclass.query call.

Signed-off-by: Art Rhyno <art632000@yahoo.ca>
Signed-off-by: Dan Scott <dscott@laurentian.ca>