Replace HaversineIntermediate with HaversineLineInterpolatePoint and HaversineDensify about geo

[michaelkirk]

Oh man, the plot thickens.

Maybe we shouldn't just get rid of HaversineIntermediate, because there are sibling traits: GeodesicIntermediate and RhumbIntermediate.

I don't have a solution yet and have run out of time to think about this today, but I'm open to proposals about how to re-align things to increase uniformity and decrease redundancy.

[JosiahParry]

One option would be to have an IntermediatePoint trait that requires an enum like DistanceType::Rhumb, DistanceType::Haversine, DistanceType::Euclidean, DistanceType::Geodesic. Then, for simplicity have convenience functions in the module.

fn intermediate_haversine(start: &Point, end: &Point, prop: f64) {}
fn intermediate_geodesic(start: &Point, end: &Point, prop: f64) {}
fn intermediate_euclidean(start: &Point, end: &Point, prop: f64) {}
fn intermediate_rhumb(start: &Point, end: &Point, prop: f64) {}