Rewritten the medial axis algorithm, now more robust (don't just prune MAT from endpoints, but validate all single edges)

xs/src/libslic3r/Polyline.cpp

@@ -4,6 +4,7 @@
 #include "Line.hpp"
 #include "Polygon.hpp"
 #include <iostream>
+#include <utility>
 
 namespace Slic3r {
 
@@ -235,4 +236,12 @@ ThickPolyline::thicklines() const
     return lines;
 }
 
+void
+ThickPolyline::reverse()
+{
+    Polyline::reverse();
+    std::reverse(this->width.begin(), this->width.end());
+    std::swap(this->endpoints.first, this->endpoints.second);
+}
+
 }