The existing code design ONLY allowed textboxes to be linked if they
were basically processed sequentially or reverse sequentially.
It appears that the processing is actually based on the order that
the textboxes were created, which is usually sequential
but not necessarily.

Change-Id: Ieb7b37d4cbd4b3a5b5d474803abccfa198a5864b
Reviewed-on: https://gerrit.libreoffice.org/16353Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Justin Luth <justin_luth@sil.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>