Make standard gfx calls on every frame in file-explorer

ctru-rs/examples/file-explorer.rs

@@ -62,6 +62,8 @@ impl<'a> FileExplorer<'a> {
                 self.get_next_path();
             }
 
+            self.gfx.flush_buffers();
+            self.gfx.swap_buffers();
             self.gfx.wait_for_vblank();
         }
     }