[libgdx] Fixed pooled track entries not resetting mixBlend.

closes #1746

spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/AnimationState.java

@@ -726,6 +726,7 @@ public class AnimationState {
 		entry.interruptAlpha = 1;
 		entry.mixTime = 0;
 		entry.mixDuration = last == null ? 0 : data.getMix(last.animation, animation);
+		entry.mixBlend = MixBlend.replace;
 		return entry;
 	}