Area is 0 if wrong winding order

[JoelBennett]

If passing in geojson that has an outer ring with a clockwise winding order, it return an area of 0. The revised geojson spec says that the outside ring should have a counterclockwise winding order. I'd think that it should either raise an exception (because the geojson is invalid) or return a negative area. Right now it seems to be returning 0, which is a bit counter-intuitive.

[astrojuanlu]

...also if you pass a Feature instead of a geometry.