Also ensure that transliteration-spellout and
(transliteration-format,transliteration-style) are mutually
exclusive and transliteration-spellout is only written if ODF
version is >1.2, namespace 'loext' for 1.2 with extensions and
namespace 'number' in anticipation of ODF 1.3 (may need to be
adapted).

Change-Id: I371dee8883ecb0d4638510c92b4bf59acd09f636
Reviewed-on: https://gerrit.libreoffice.org/55491Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Eike Rathke <erack@redhat.com>