new feature: spacer, set needUpdate after addChild/addChildAt
new feature: spacer,
set needUpdate after addChild/addChildAt

brean/pixi_ui,brean/pixi_ui,leftees/gown.js,FlorianLudwig/gown.js,leftees/gown.js,brean/pixi_ui,leftees/gown.js,FlorianLudwig/gown.js,leftees/gown.js,FlorianLudwig/gown.js,FlorianLudwig/gown.js,brean/pixi_ui