[get_turns] fix invalid equal<> use (convert() for uninitialized Point) in get_turn_info_for_endpoints and get_turn_info_linear_areal
[get_turns] Fix test for L/L and L/A - missing functions in expected_pusher range
Merge branch 'develop' into rescale_to_integer
[get_turns] Fix after merge: use base_turn_handler::assign_point() instead of bg::convert() in L/L and L/A

The new function must be used because besides the copying of an intersection point fractions must be set in turns.
Apply the change in get_turn_info_for_endpoints and get_turn_info_linear_areal.