[Koha] UNIMARC to MARC21 translation UPDATED xsl

[Theodoros Theodoropoulos]

Dear all,

I have just uploaded to BZ a big update of the original UNIMARC->MARC21 
xsl that was currently available.

You may find the file in the appropriate BZ case 
(https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=16488) and 
test it for yourself.
You must copy the file to koha-tmpl/intranet-tmpl/prog/en/xslt/
And then put "UNIMARC2MARC21.xsl" in "XSLT File(s) for transforming 
results:" textfield of a UNIMARC Z39.50 source that you wish to 
translate to MARC21

The new version has better handling of Unimarc-100 (MARC21-008) field, 
and supports the translation of far more UNIMARC fields.

Almost all of the code was based on the (almost 15-year-old!) conversion 
guidelines by LOC, so some fields/subfields might now be deprecated.
Even worse, important new fields might be missing from the translation.
(856 field was such an example, so by reading more recent docs, I think 
I translated it properly).

Warnings:
- The work is nowhere near complete, but it's better (and more complete) 
that what was currently available online.
- My knowledge of UNIMARC is very-very limited.
- The xsl was not thoroughly tested and the time I had to spend on it 
was limited. Expect to find errors :)

Known issues:
Although the xsl /seems/ to work fine for me, there are certain encoding 
issues when using it to IMPORT utf8 UNIMARC records to Koha. Displaying 
of UTF8 records in the Koha Z39.50 result list is OK, but importing them 
to cataloging is not.
It's possible that it's an issue of Koha code and not related to this 
xsl. (I will open a BZ case soon).


Best regards,
Theodoros Theodoropoulos