Memory optimizations, multithreading fixes, uCore updated

server/src/io/anuke/mindustry/server/MindustryServer.java

@@ -2,6 +2,7 @@ package io.anuke.mindustry.server;
 
 import io.anuke.mindustry.Vars;
 import io.anuke.mindustry.core.*;
+import io.anuke.mindustry.game.Content;
 import io.anuke.mindustry.io.BundleLoader;
 import io.anuke.ucore.modules.ModuleCore;
 
@@ -22,6 +23,7 @@ public class MindustryServer extends ModuleCore {
 
         BundleLoader.load();
         ContentLoader.load();
+        ContentLoader.initialize(Content::init);
 
         module(logic = new Logic());
         module(world = new World());