- Make returning LatLngs unwrapped by default.
- PointAnnotation and ShapeAnnotation are always wrapped so they can be
selected via intersection from the visible tile boundaries.
- Fixes LatLng::wrap() calculation.
- Fixes LatLng::unwrapForShortestPath() calculation.
The new unwrapForShortestPath algorithm unwraps the start coordinate
either forwards or backwards depending on the end coordinate value, so
we can always cross the antimeridian when needed and still obtain a
wrapped end coordinate in the end.
Fixes#4214.
* Use "named constructors": empty, world, hull
* Make the two-argument constructor lenient (i.e., it is a hull operation)
* Add various accessors
* Enforce a single empty representation
