message: Use local lambda to format resource difference
diff: using namespace NAS2D;
  -namespace
  -{
  - std::string formatDiff(int diff)
  - {
  - return ((diff > 0) ? "+" : "") + std::to_string(diff);
  - }
  -}
  -
  -
  ResourceBreakdownPanel::ResourceBreakdownPanel() :
  mFont{fontCache.load(constants::FONT_PRIMARY, constants::FONT_PRIMARY_NORMAL)},
  mIcons{imageCache.load("ui/icons.png")},
  @@ -47,6 +38,9 @@ void ResourceBreakdownPanel::update()
  auto& renderer = Utility<Renderer>::get();
  mSkin.draw(renderer, mRect);
  + const auto formatDiff = [](int diff){
  + return ((diff > 0) ? "+" : "") + std::to_string(diff);
  + };
  const auto trendIndex = [](int newValue, int oldValue){
  return
  (newValue == oldValue) ? 0 :
  