[disjoint] Fix A/A by replacing point_on_surface with point_on_boundary and changing relation check.
[test][disjoint] Add tests for A/A
[disjoint] Replace has_within with not_disjoint and set it instead of checking conditions.
[disjoint] Update a comment about point on border.
Merge pull request #163 from awulkiew/fix/disjoint

Fix/disjoint