No intersection for polygons with close boundaries

[mjacobse]

No intersection is returned for the example

where the intersection should basically be the green polygon. This is on develop with #1479 already merged.

Here is the example written as test case: mjacobse@42e03ee
It fails with the output

libs/geometry/test/algorithms/set_operations/intersection/test_intersection.hpp(137): error: in "test_main_caller( argc_ argv )": intersection: issue_1487 #outputs expected: { 1} detected: 0 type: d
libs/geometry/test/algorithms/set_operations/intersection/test_intersection.hpp(155): error: in "test_main_caller( argc_ argv )": intersection: issue_1487 #area expected: 18983.884971862571547 detected: 0 type: d
libs/geometry/test/algorithms/set_operations/intersection/test_intersection.hpp(137): error: in "test_main_caller( argc_ argv )": intersection: issue_1487 #outputs expected: { 1} detected: 0 type: d ccw
libs/geometry/test/algorithms/set_operations/intersection/test_intersection.hpp(155): error: in "test_main_caller( argc_ argv )": intersection: issue_1487 #area expected: 18983.884971862571547 detected: 0 type: d ccw