Exclude planned building from address file import

According to the content-related description of the used dataset, the
dataset includes both already built coordinates (quality "A") and
coordinates on the parcel for planned buildings (quality "R") (see [0]).

As OpenStreetMap only includes existing buildings, this commit excludes
all quality "R" coordinates.

[0] http://fbinter.stadt-berlin.de/fb_daten/beschreibung/sachdaten/s_hauskoordinaten.html

Bear with me if something is wrong - I haven't coded any PHP for 10 years.

And btw, thanks for the nice & useful service.