restrict number of results for reverse queries

restrict number of results for reverse queries

When given a coordinate off the coast of a large town, the entire
town may end up in the potential results during the reverse query.
Postgres then needs to sort tens of thousands of results before it
can determine the clostest one. Given that the results at such a
large search radius are bound to be imprecise anyway, restrict
the number of results postgres should consider to 1000.