Only register changes in ReplayFileAppender if something changed - this applies to GuiKeyframeRepository, GuiObjectManager, GuiPlayerOverview, GuiAssetManager

Added equals method to ReplayImageAsset which is based on the BufferedImage's hash code (which is calculated only once)

src/main/java/eu/crushedpixel/replaymod/utils/BufferedImageUtils.java

@@ -0,0 +1,13 @@
+package eu.crushedpixel.replaymod.utils;
+
+import java.awt.image.BufferedImage;
+import java.awt.image.DataBufferByte;
+import java.util.Arrays;
+
+public class BufferedImageUtils {
+
+    public static int hashCode(BufferedImage bi) {
+        byte[] data = ((DataBufferByte) bi.getData().getDataBuffer()).getData();
+        return Arrays.hashCode(data);
+    }
+}