reworked container access (never throw, multi-field access, return values, operator), added package storage

src/main/java/carpet/CarpetServer.java

@@ -111,6 +111,7 @@ public class CarpetServer // static for now - easier to handle all around the co
 
     public static void onServerClosed(MinecraftServer server)
     {
+        scriptServer.onClose();
         LoggerRegistry.stopLoggers();
         extensions.forEach(e -> e.onServerClosed(server));
     }