handle docx's w:anchor layoutInCell attribute (bnc#891663)

Change-Id: I8268567b84aa0f6e42624bfd0f79c8c49c153edd
Reviewed-on: https://gerrit.libreoffice.org/11568
Reviewed-by: Andras Timar <andras.timar@collabora.com>
Tested-by: Andras Timar <andras.timar@collabora.com>