Using the address rank to set the address parts catches
a much wider variety of types like 'town' and 'suburb'.
With recent address ranking changes the rank ranges
are relatively reliable.
By starting with the lowest address level, when collecting
administrative boundaries by level, there is a better chance
to actually get the boundary when the capital of the
administrative boundary is tagged with the level of the
boundary as well.
This is just a heuristics adaption to make the best out of
the imprecise admin_level definition for place nodes.
Fixes#1261.
Introduces new AddressDetails class which is responsible
for address lookups. Saves always the complete result
and then allows filtering throught the different access
function. Remove special handling in Geocode() and use
there the lookup throught PlaceLookup() as well.
