message: Fix rebuilding
  The scoping is important as later on in the
  rebuild function, functions are being called
  which borrow the RefCell as well.
diff: @@ -145,8 +145,10 @@ impl Display {
  };
  // Replace the stored WindowedContext with the new one.
  + {
  let mut gl_window = self.gl_window.borrow_mut();
  Takeable::insert(&mut gl_window, new_gl_window);
  + }
  // Rebuild the Context.
  let backend = GlutinBackend(self.gl_window.clone());
  