Add a missing import
Add an option for setting local search radius

Looks like it indeed influences the returned results quite a bit:
* if a small radius is used, results in the radius are returned
* if a bigger radius is used many of the results from the small
  radius are skipped and replaced by results farther away
Also rename the options to just Local search from Google Local search
as there might be other local search providers in the future with
common options.