Structures Update and Touch-Ups

Add a structures update that adds new structures to Minecraft, or a small game drop adding one big one or a few small ones. I always get excited when I learn of a new structure, like the abandoned camps or the trial chambers, but these updates are way to far apart. A structure gives a player a new goal to accomplish, such as visit an ancient city, or find the secret room in a jungle temple. They also add to the mystery of the world and to the average time that players will spend on one world. Also consider updating older structures such as the mansion or the jungle temple with new blocks and features, such as cushions or better loot.