message: Use new delegate Button constructor in GameOverDialog
diff: @@ -12,14 +12,13 @@ using namespace NAS2D;
  GameOverDialog::GameOverDialog() :
  mHeader{imageCache.load("ui/interface/game_over.png")},
  - btnClose{"Return to Main Menu"}
  + btnClose{"Return to Main Menu", {this, &GameOverDialog::onClose}}
  {
  position({0, 0});
  size({522, 340});
  add(btnClose, {5, 310});
  btnClose.size({512, 25});
  - btnClose.click().connect(this, &GameOverDialog::onClose);
  anchored(true);
  }
  