Rewrote Fill2.pm to C++, deleted Perl infills for good.

Removed dependency on Perl Math::PlanePath module.
Fixed compilation with Visual Studio and SLIC3R_DEBUG: Visual Studio older than 2015 does not support the prinf type specifier %zu. Use %Iu instead.
C++11 move semantics enabled.

xs/xsp/ExtrusionEntityCollection.xsp

@@ -11,8 +11,7 @@
     Clone<ExtrusionEntityCollection> clone()
         %code{% RETVAL = THIS->clone(); %};
     void reverse();
-    void clear()
-        %code{% THIS->entities.clear(); %};
+    void clear();
     ExtrusionEntityCollection* chained_path(bool no_reverse)
         %code{%
             RETVAL = new ExtrusionEntityCollection();

xs/xsp/Filler.xsp

@@ -4,6 +4,8 @@
 #include <xsinit.h>
 #include "libslic3r/Fill/Fill.hpp"
 #include "libslic3r/PolylineCollection.hpp"
+#include "libslic3r/ExtrusionEntity.hpp"
+#include "libslic3r/ExtrusionEntityCollection.hpp"
 %}
 
 %name{Slic3r::Filler} class Filler {
@@ -63,5 +65,13 @@ new_from_type(CLASS, type)
     OUTPUT:
         RETVAL
 
+void
+make_fill(CLASS, layer_region, out_append)
+    char*                       CLASS;
+    LayerRegion*                layer_region;
+    ExtrusionEntityCollection*  out_append;
+    CODE:
+        make_fill(*layer_region, *out_append);
 %}
+
 };

xs/xsp/Layer.xsp

@@ -96,6 +96,7 @@
     bool any_bottom_region_slice_contains_polyline(Polyline* polyline)
         %code%{ RETVAL = THIS->any_bottom_region_slice_contains(*polyline); %};
     void make_perimeters();
+    void make_fills();
 
     void export_region_slices_to_svg(const char *path);
     void export_region_fill_surfaces_to_svg(const char *path);