These are used to mark large paved areas. Sometimes they exists
together with named regular streets. In such cases the unnamed
area may overshadow the actual street when computing the address
parent. As unnamed highways are not very useful anyway, we
simply remove them from the database.
Postal boundaries usually just have the postcode tag set and are
therefore officially 'nameless'. We want to have them as
boundary=postal_code anyways in order to distiguish them from postcode
points inherited from addr: tags.
Remove unnamed landuses and postcode points from
importing. The latter will cause all objects with
address tags to be imported after all. Not expected
in the admin import style.