Add support for Geospatial Properties

It would be awesome to see geo functionalities such as described here: http://www.odata.org/blog/geospatial-properties/

```
/Me/Friends$filter=geo.distance(PlannedLocations, geography'SRID=12345;POINT(-127.89734578345
        45.234534534)' lt 900.0 and PlannedTime eq datetime'2011-12-12T13:36:00'
```

Any plans to integrate it in the road map?