– new Bulgarian and Icelandic language support
– fixes of language data based on libreoffice-l10n's patches
  and feedback (see ChangeLog in the external package for details)

Change-Id: I98598747c8b4e8e7fba380998c6ebbc1f63fef2e
Reviewed-on: https://gerrit.libreoffice.org/54936Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: László Németh <nemeth@numbertext.org>