[distance] Do not use cartesian default strategy for non-cartesian Pt/Box and Box/Box
[distance] Add preliminary version of Pt/Box spherical strategy.
[strategies] Add move course() to algorithms/detail and use it in spherical side and distance strategies.
[distance] Optimize cross_track_point_box - calculate courses only once, do not use other strategies than PP
[distance] Fix compilation error in get_comparable<> specialization for distance_cross_track_point_box<>
[convex_hull] Fix invalid number of Points generated for open OutputGeometry.
[test][convex_hull] Add tests for open output Geometries.
[convex_hull] Generate consistent results for closed and open Geometries.

The result differ only for the last Point duplicated for closed.
This code should be faster than the original since any condition isn't checked inside a copying loop and the end iterators are created only once.
[test][convex_hull] Add test for MultiPoint for which convex_hull() should return invalid Polygon.
[convex_hull] Generate "proper" number of Points also when invalid Output is generated.

E.g. for 1- or 2-Point MultiPoint input the Output is a 0-area Ring (Point-like or Segment-like respectively). After this change it should contain "proper" number of Points (3 for open, 4 for closed). The additional Point is added by duplication of the first one.
[test][convex_hull] Update convex_hull tests.

Update multi_convex_hull test to reflect recently made changes for Point-like and Segment-like Output.

Remove the test for MultiPoint from convex_hull test since it's already tested in multi_convex_hull test.
[test][centroid] Add test for big doubles.
[test][to_svg] Add geom_to_svg() helper function.
[test][centroid] Improve the test for Polygon using big coordinates.
[centroid] Reduce numerical errors by translating the Geometry closer to 0 and then the result back.

The first Point of the Geometry is used as the new origin.
During the centroid calculation each Point is translated by subtracting the origin.
At the end the resulting point is translated back by adding the origin.
[centroid] Disable error-reducing translation for other coordinate systems than cartesian.

Remove undefined namespace.
Add missing headers.
Add a note about other coordinate systems.
Add copyright info.
[centroid] Disable translation for non-areal Geometries.
[algorithms][distance] replace ignore_unused_variable_warning by ignore_unused
[algorithms][closest_feature] add algorithm for computing the closest
feature between a point and an open/closed range of segments (represented
as a range of points
[algorithms][closest_feature] add algorithm for computing the pair of
closest features between two ranges, using the R-Tree