Bug 25247: Only convert data ot objects when displaying on screen

Bug 25247: Only convert data ot objects when displaying on screen

To test:
 1 - Modify a patron
 2 - Circulate some items to the patron
 3 - Click 'Modification log'
 4 - Verify you see your actions
 5 - Under 'Output' select 'To a file'
 6 - Save the output to a file
 7 - View the file
 8 - Not you have references ot objects in stead of patron/item data
 9 - Apply patch
10 - Repeat
11 - Note viewing on screen has not changed
12 - Note exporting to file inlcudes borrower/item numbers and not references
13 - Sign off

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>