message: Use vector operation to center MainMenuState background image
diff: @@ -329,7 +329,7 @@ NAS2D::State* MainMenuState::update()
  Renderer& r = Utility<Renderer>::get();
  r.clearScreen(0, 0, 0);
  - r.drawImage(mBgImage, r.center_x() - mBgImage.width() / 2, r.center_y() - mBgImage.height() / 2);
  + r.drawImage(mBgImage, r.center() - mBgImage.size() / 2);
  if (!mFileIoDialog.visible() && !dlgOptions.visible())
  