Support GEO search

[BagritsevichStepan]

We need to support GEO search as requested here.

For example:

127.0.0.1:6379> HSET place:1 name "Eiffel Tower" location "2.2945,48.8584"
(integer) 2
127.0.0.1:6379> HSET place:2 name "Louvre Museum" location "2.3358,48.8606"
(integer) 2
127.0.0.1:6379> HSET place:3 name "Notre-Dame" location "2.3499,48.8529"
(integer) 2
127.0.0.1:6379> FT.CREATE index ON HASH PREFIX 1 "place:" SCHEMA name TEXT location GEO 
OK
127.0.0.1:6379> FT.SEARCH index "*" GEOFILTER location 2.2945 48.8584 5 km
1) (integer) 3
2) "place:1"
3) 1) "name"
   2) "Eiffel Tower"
   3) "location"
   4) "2.2945,48.8584"
4) "place:2"
5) 1) "name"
   2) "Louvre Museum"
   3) "location"
   4) "2.3358,48.8606"
6) "place:3"
7) 1) "name"
   2) "Notre-Dame"
   3) "location"
   4) "2.3499,48.8529"