去掉obi，使用自写绳索

Assets/Obi/Scripts/Common/DataStructures/ParticlePair.cs

@@ -1,24 +0,0 @@
-using UnityEngine;
-using System.Collections;
-
-
-namespace Obi
-{
-    public struct ParticlePair
-    {
-        public int first;
-        public int second;
-
-        public ParticlePair(int first, int second)
-        {
-            this.first = first;
-            this.second = second;
-        }
-
-        public int this[int index]
-        {
-            get { return index == 0 ? first : second; }
-            set { if (index == 0) first = value; else second = value; }
-        }
-    }
-}