去掉obi，使用自写绳索

Assets/Obi/Scripts/Common/Backends/Burst/Constraints/Tether/BurstTetherConstraints.cs

@@ -1,26 +0,0 @@
-#if (OBI_BURST && OBI_MATHEMATICS && OBI_COLLECTIONS)
-using System;
-
-namespace Obi
-{
-    public class BurstTetherConstraints : BurstConstraintsImpl<BurstTetherConstraintsBatch>
-    {
-        public BurstTetherConstraints(BurstSolverImpl solver) : base(solver, Oni.ConstraintType.Distance)
-        {
-        }
-
-        public override IConstraintsBatchImpl CreateConstraintsBatch()
-        {
-            var dataBatch = new BurstTetherConstraintsBatch(this);
-            batches.Add(dataBatch);
-            return dataBatch;
-        }
-
-        public override void RemoveBatch(IConstraintsBatchImpl batch)
-        {
-            batches.Remove(batch as BurstTetherConstraintsBatch);
-            batch.Destroy();
-        }
-    }
-}
-#endif