Advancement stars

When you complete an advancement extra crazy, like deflecting a fireball with an arrow for Return to Sender or getting an iron pickaxe before you get a stone one for Isn't it Iron pick, a gold star appears on the advancement and it turns blue in the menu. Doing this also awards more experience. There is also a new star parameter for /advancement, which decides whether a star appears and it turns blue. Can be set to true or false.