Latitude longitude filter

Latitude/Longitude filter:

This filter let you define points and a radius in order to define areas. Then, the filter could discard bid requests not belonging to those areas.

Agent config example to use the filter:

{
...
"latLongDevFilter": [{"lat": 37.123, "radius": 15.5, "long": -92.456}]
...
} 

Yes you are rigth ! i will erase this PR and create another with that modification.