Add lat/lng report filtering support

[mjurkus]

Allow to filter by lat and lng.

I guess it should accept lat_from lat_to lng_from lng_to? Or is there a better way? And return matching results in a given box.

@laurynas

[laurynas]

Yes, from/to coordinates would be most straightforward. Another option would be to use geokit-rails gem which would searching by center coords and radius.

Which way would you prefer?

[mjurkus]

Let's choose straightforward approach.

[laurynas]

Deployed.