Removed MarkerKeyframe and replaced it with generic type of Keyframe using the new Marker POJO

src/main/java/eu/crushedpixel/replaymod/holders/Marker.java

@@ -0,0 +1,20 @@
+package eu.crushedpixel.replaymod.holders;
+
+import eu.crushedpixel.replaymod.interpolation.KeyframeValue;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+public class Marker implements KeyframeValue {
+
+    private String name;
+    private AdvancedPosition position;
+
+    @Override
+    public KeyframeValue newInstance() {
+        return new Marker();
+    }
+}

src/main/java/eu/crushedpixel/replaymod/holders/MarkerKeyframe.java

@@ -1,14 +0,0 @@
-package eu.crushedpixel.replaymod.holders;
-
-import lombok.AllArgsConstructor;
-import lombok.Data;
-
-@Data
-@AllArgsConstructor
-public class MarkerKeyframe {
-
-    private int realTimestamp;
-    private AdvancedPosition position;
-    private String name;
-
-}