For aqbanking, take into account the actual purpose line length that is given from aqbanking.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23662 57a11ea4-9604-0410-9ed3-97b8803252fd
Update aqbanking code for latest aqbanking development.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23663 57a11ea4-9604-0410-9ed3-97b8803252fd