Able to search by latitude and longitude

[esong]

Should we add radius_filter to the query? Maybe we can add it in the next pull request.

I tested it with http://127.0.0.1:9000/search?term=restaurant&lati=43.473180&longi=-80.533892, the geo location is very close to lester st, but the results are on King st, it's probably because they have higher rating and reviews.

[zhuhw]

Added radius_filter

[esong]

老爷辛苦了