FIX: rewrite per-object printing order logic

1. Previous logic can't guarantee left-to-right printing order, so
   toolhead may crash on the right side. In the new algorithm printing
   order is guaranteed.
2. Clearance radius should be the max of 3 directions (left, bottom,
   up), not including right, otherwise collision may happen on bottom or
   up directions.
3. Add is_extrusion_cali_object property to handle extrusion brim
   overlap better.

Change-Id: I44868b9925d983f5cca0c31d35dfa28d895fadbf

src/slic3r/GUI/PartPlate.cpp

@@ -3461,6 +3461,7 @@ bool PartPlateList::preprocess_nonprefered_areas(arrangement::ArrangePolygons& r
 			ret.translation = Vec2crd(0, 0);
 			ret.rotation = 0.0f;
 			ret.is_virt_object = true;
+            ret.is_extrusion_cali_object = true;
 			ret.bed_idx = j;
 			ret.height = 1;
 			ret.name = "NonpreferedRegion" + std::to_string(index);