Clear method for animation state.

spine-csharp/src/AnimationState.cs

@@ -59,6 +59,11 @@ namespace Spine {
 			Time = 0;
 		}
 
+		public void Clear () {
+			previous = null;
+			Animation = null;
+		}
+
 		override public String ToString () {
 			return (Animation != null && Animation.Name != null) ? Animation.Name : base.ToString();
 		}

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

@@ -60,6 +60,11 @@ public class AnimationState {
 			current.apply(skeleton, currentTime, currentLoop);
 	}
 
+	public void clear () {
+		previous = null;
+		current = null;
+	}
+
 	/** @see #setAnimation(Animation, boolean) */
 	public void setAnimation (String animationName, boolean loop) {
 		Animation animation = data.getSkeletonData().findAnimation(animationName);