[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<>
[buffer] fix comment
[buffer] add new failing testcases (now 9 out of 500000 fail for miter)
[buffer] block turns instead of discarding them
This fixes case rt_u11
New result of recursive_polygons_buffer: 2 errors out of 510372
[buffer][test] add failing test for which there is not yet a solution.
It is related to colocated turns and sorting
[buffer][test] make labels for turns optional, for good turns and for bad turns
Merge branch 'develop' into feature/buffer
[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.
[overlay][relate][is_valid][buffer] Remove other_id from turn_operation.
[overlay][is_valid] Replace int with signed_index_type for segments indexes.
[overlay] Move signed_index_type to separate file. Clean headers in ring_ and segment_identifier.hpp.