add reverse curved rail

rails-courbes-reverse.scad

@@ -0,0 +1,8 @@
+mirror([1,1,0]) union(){
+translate( [0,0,0]) 
+    linear_extrude (height=2)
+        import (file="rails.dxf", layer="rails-courbes-traverses", $fn=100);
+translate( [0,0,1.99]) 
+    linear_extrude (height=2.4)
+        import (file="rails.dxf", layer="rails-courbes", $fn=100);
+}