[get_turns] Fix for L/L spike vs. endpoint for the same direction segments. Add failing test cases for spikes touching internal point
Merge branch 'develop' of github.com:boostorg/geometry into develop
[get_turns] Fix the generation of some special cases of touch-spike-turns for L/L and L/A
[get_turns] Fix invalid condition get_turn_info_la
[get_turns] Add more tests for t-spikes for L/L
[get_turns] Add tests for t-spikes vs collinear internal pt for L/L
[relate][test] Enable tests for 2-Point degenerated Linestrings
[intersection] fix segments_intersection_ratios
adding the new one_degenerate method
fixed comment
[get_turns] Use RobustPolicy in a unified way in all three get_turn_info* policies (A/A, L/A, and L/L).

Newly introduced intersection_info containing IntersectionResult, SideCalculator and Point refs is used also in get_turn_info for A/A.
Robust points are stored only if RobustPolicy is not no_rescale_policy.
This commit also fixes an error in get_turn_info - swapped_side_calc created for method_touch_interior ('m') should use robust points just like the original one.
[get_turns] Fix turn operation is_collinear values for L/L and L/A.

is_collinear for the first endpoint of L is now unified and is always equal to FALSE.

Add tests of is_collinear. It is tested by passing 4th and 5th char in the expected turn string (= means collinear, + means non-collinear), e.g. "mxi=+" for L/L means that L1 ends in this IP and was collinear before meeting the Point, L2 is going "inside" intersection and wasn't collinear before.

Replace method_and_operation_replacer with turn_transformer.
Merge branch 'develop' of https://github.com/boostorg/geometry into feature/point_iterator