Bug 11559: (followup) Prevent saving item tags, fix other issues
This fixes the following issues:
* Spaces are now allowed in indicators
* Shift-Enter is available to insert a newline if needed
* Item tags, if present, will prevent saving (as they are not correctly
processed by the backend)
* biblionumber tags (999 in MARC21) will be stripped before the record
is saved to Koha, to prevent their modification
Signed-off-by: Nick Clemens <nick@quecheelibrary.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>