Ported three PrintObject methods to XS

xs/src/libslic3r/Print.hpp

@@ -103,6 +103,9 @@ class PrintObject
     ModelObject* model_object();
     
     Points copies() const;
+    bool add_copy(const Pointf &point);
+    bool delete_last_copy();
+    bool delete_all_copies();
     bool set_copies(const Points &points);
     bool reload_model_instances();
     

xs/src/libslic3r/PrintObject.cpp

@@ -53,6 +53,29 @@ PrintObject::copies() const
     return this->_copies;
 }
 
+bool
+PrintObject::add_copy(const Pointf &point)
+{
+    Points points = this->_copies;
+    points.push_back(Point::new_scale(point.x, point.y));
+    return this->set_copies(points);
+}
+
+bool
+PrintObject::delete_last_copy()
+{
+    Points points = this->_copies;
+    points.pop_back();
+    return this->set_copies(points);
+}
+
+bool
+PrintObject::delete_all_copies()
+{
+    Points points;
+    return this->set_copies(points);
+}
+
 bool
 PrintObject::set_copies(const Points &points)
 {