Added pingpongReverse to SequenceTimeline.

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

@@ -2494,16 +2494,22 @@ public class Animation {
 				case loop:
 					index %= count;
 					break;
-				case pingpong:
+				case pingpong: {
 					int n = (count << 1) - 2;
 					index %= n;
 					if (index >= count) index = n - index;
 					break;
+				}
 				case onceReverse:
 					index = Math.max(count - 1 - index, 0);
 					break;
 				case loopReverse:
 					index = count - 1 - (index % count);
+					break;
+				case pingpongReverse:
+					int n = (count << 1) - 2;
+					index = (index + count - 1) % n;
+					if (index >= count) index = n - index;
 				}
 			}
 			slot.setSequenceIndex(index);