Let's default to 12x36 cells.

Change-Id: Ic39739ec036a6e5867d31b7e05b6da12ce2e46d2
Reviewed-on: https://gerrit.libreoffice.org/16413Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>