6769 Getting rid of some RIS errors/warnings

6769 Getting rid of some RIS errors/warnings

Removing unnecessary warnings. Some were based on errors in the script. Others are removed by adding debug flag and disabling debugging mode by default.
Adding carriage returns for Windows users, assuming that it does not hurt the Linux users. (Perhaps a future option?)
Test it with: http://yourserver.com/cgi-bin/koha/opac-export.pl?bib=yourbibnumber&format=ris&op=export [replace server and biblionumber]

Revision of Aug 24: Fixed two missing newlines too.

Signed-off-by: Steven Callender <stevecallender@esilibrary.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>
  (removed comment "240811 marcelr during QA"

Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>