Add tests:
- test_meta
- test_meta_empty
- test_meta_field
- test_meta_field_empty
- test_bookmark1
- test_bookmark2
- test_refmark2
- test_refmark3
- test_toxmark2
- test_toxmark3
Change-Id part 1: I0920517b5e8806a5fc46708822fed33006f03fd5

Change-Id: If8e50aa036f10caf1b460c041dd7bce068f9cd7b
Reviewed-on: https://gerrit.libreoffice.org/38842Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>