Removed drawing until it is supported for rational curves

Arrangement_on_surface_2/examples/Arrangement_on_surface_2/rational_functions.cpp

@@ -2,7 +2,6 @@
 // Constructing an arrangement of arcs of rational functions.
 
 #include <CGAL/config.h>
-#include <CGAL/draw_arrangement_2.h>
 
 #ifndef CGAL_USE_CORE
 #include <iostream>
@@ -57,8 +56,6 @@ int main() {
   insert(arr, arcs.begin(), arcs.end());
   print_arrangement(arr);
 
-  CGAL::draw(arr, "rational_functions");
-
   return 0;
 }