Bug 6098 Followup -- doesn't replace NSB/NSE by space

Bug 6098 Followup -- doesn't replace NSB/NSE by space

On any page, NSB/NSE characters are replaced by space in Output.pm. It isn't a
good thing:

  - It isn't necessary since Zebra indexer handle properly those characters as
    delimiter.
  - It isn't necessary for display since XSL file already do that.
  - It isn't efficient since a regex is done on every whole page sent by Koha,
    not only on biblio record part.
  - It removes an information that librarian want to keep in their biblio
    records: any record edited in Koha loose its NSB/NSE characters.

Signed-off-by: Frédéric Demians <f.demians@tamil.fr>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>