Generation of 3D-steps shorter than 3D tolerance has been allowed in the fix to build Walking-line.
Now, 3D-step is limited by Precision::Confusion value.
Purger has been disabled (in IntPatch_PrmPrmIntersection algorithm) if some points have been added in the Walking line (it is stupidly, first, to insert some points in the line and, after that, to delete points from this line).
Some improvements in IntWalk_PWalking::SeekPointOnBoundary(...) method have been made (see comments in the code for detail information).
Some test cases have been adjusted according to their new behavior.
