Empty geocoding results aren't always cached

Thanks for working on this.

Are we sure we want to cache the results on exceptions? Exceptions can be temporary and could happen in special cases / network errors or similar:

$msg = t('HTTP request to Bing API failed.\nCode: @code\nError: @error', $args);
throw new Exception($msg);

Does this have any benefit / drawbacks?

Otherwise, if the call $geometry = call_user_func($processor['callback'], $data, $options); returns NULL/empty results, it will make its way to the geocoder_cache_set(), so I think this works correctly. Only if there is an exeption the result is not cached. Thanks!