Speed up encloses_point calls from medial_axis code.
Speed up encloses_point calls from medial_axis code.

The points shouldn't be on hole borders so we can make the check
much quicker.  Gives over 50% speed up slicing reprap shot glass
(thing:11944) with default settings and 0.3 layer height.

prusa3d/Slic3r,lordofhyphens/Slic3r,xoan/Slic3r,mcilhargey/Slic3r,lordofhyphens/Slic3r,tmotl/Slic3r,tmotl/Slic3r,tmotl/Slic3r,curieos/Slic3r,pieis2pi/Slic3r,xoan/Slic3r,tmotl/Slic3r,alexrj/Slic3r,platsch/Slic3r,platsch/Slic3r,pieis2pi/Slic3r,lordofhyphens/Slic3r,curieos/Slic3r,curieos/Slic3r,alexrj/Slic3r,curieos/Slic3r,mcilhargey/Slic3r,mcilhargey/Slic3r,tmotl/Slic3r,prusa3d/Slic3r,lordofhyphens/Slic3r,xoan/Slic3r,pieis2pi/Slic3r,alexrj/Slic3r,curieos/Slic3r,platsch/Slic3r,xoan/Slic3r,mcilhargey/Slic3r,alexrj/Slic3r,mcilhargey/Slic3r,mcilhargey/Slic3r,prusa3d/Slic3r,xoan/Slic3r,tmotl/Slic3r,prusa3d/Slic3r,alexrj/Slic3r,platsch/Slic3r,prusa3d/Slic3r,platsch/Slic3r,curieos/Slic3r,alexrj/Slic3r,pieis2pi/Slic3r,pieis2pi/Slic3r,mcilhargey/Slic3r,pieis2pi/Slic3r,platsch/Slic3r,prusa3d/Slic3r,xoan/Slic3r,lordofhyphens/Slic3r,lordofhyphens/Slic3r,prusa3d/Slic3r