Bug 9045 - Adding some parameters to export_borrowers.pl

Bug 9045 - Adding some parameters to export_borrowers.pl

Followup : Adding test if results has some records and usage example for
--where clause

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
I infer from the bug comments that a proper test for this patch is to
check how the script reacts if it returns no results with a --where
clause, and to verify that there is a good usage example for the --where
option. These are both true, so I think this passes.

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
All tests and QA script pass.

Tests done:
- tested -s option with \;
- tested -f surname -f borrowernumber to have multiple fields specified
- tested -w with "borrowernumber > 100" and similar with and without
  results - if no results a message is shown
- tested -h shows documentation for new options
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>