message: Remove C-style cast of constant
  The `fadeOut` call for `btnQuitClicked` doesn't use a cast. Perhaps the
  compiler is smart enough to silently convert constant integer values to
  floating point when they are in range. It should be reasonable for the
  compiler to do this when the definition is `constexpr` compatible.
diff: @@ -242,7 +242,7 @@ void PlanetSelectState::onMouseDown(EventHandler::MouseButton /*button*/, int /*
  {
  Utility<Mixer>::get().playSound(mSelect);
  PLANET_TYPE_SELECTION = mPlanets[i]->type();
  - Utility<Renderer>::get().fadeOut((float)constants::FADE_SPEED);
  + Utility<Renderer>::get().fadeOut(constants::FADE_SPEED);
  Utility<Mixer>::get().fadeOutMusic(constants::FADE_SPEED);
  return;
  }
  