Sort assets by name in AssetManager and ObjectManager

src/main/java/eu/crushedpixel/replaymod/assets/ReplayImageAsset.java

@@ -40,6 +40,11 @@ public class ReplayImageAsset implements ReplayAsset<BufferedImage> {
         this.name = name;
     }
 
+    @Override
+    public String getAssetName() {
+        return name;
+    }
+
     @Override
     public void setAssetName(String name) {
         this.name = name;