Bug 12724: Show RDA tag 264 on OPAC Detail XSLT view

Bug 12724: Show RDA tag 264 on OPAC Detail XSLT view

This patch adds selected information from tag 264 to the Publisher line
on the OPAC detail XSLT view (MARC21). This includes a label, and the
subfields abc.

If Publication tag 260 exists, it adds information. If tag 260 does not exist,
it creates a 'publisher' line. (NOTE: Probably, both fields will not both be
present, but this patch can deal with that..)

Instead of showing all 264 tags, it picks the preferred one based on the
following rules (using both indicators; see LOC description):
[1] Try to select a Publisher -- Latest. Pick first one.
[2] Else try to select a Publisher. Pick the last one.
[3] Else try to select an other one (Producer, Manufacturer, ..) with Latest.
    Pick the first one of that.
[4] Otherwise: Pick the last 264 tag.

Test plan:
[1] Add one 260 and multiple 264 tags to your record.
[2] Check display in OPAC detail XSLT.
[3] Change some indicators, subfields of the 264s.
[4] Check display again, following the above rules.
    Go back to step 3 a couple of times.
[5] Remove tag 260. Check display again.

Followed test plan. Patch behaves as expected.
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>