整理代码结构，支持Package Manager添加

Scripts/Runtime/Internal/ObjectPool.cs

@@ -0,0 +1,56 @@
+/******************************************/
+/*                                        */
+/*     Copyright (c) 2018 monitor1394     */
+/*     https://github.com/monitor1394     */
+/*                                        */
+/******************************************/
+
+using System.Collections.Generic;
+using UnityEngine;
+using UnityEngine.Events;
+
+namespace XCharts
+{
+    public class ObjectPool<T> where T : new()
+    {
+        private readonly Stack<T> m_Stack = new Stack<T>();
+        private readonly UnityAction<T> m_ActionOnGet;
+        private readonly UnityAction<T> m_ActionOnRelease;
+
+        public int countAll { get; private set; }
+        public int countActive { get { return countAll - countInactive; } }
+        public int countInactive { get { return m_Stack.Count; } }
+
+        public ObjectPool(UnityAction<T> actionOnGet, UnityAction<T> actionOnRelease)
+        {
+            m_ActionOnGet = actionOnGet;
+            m_ActionOnRelease = actionOnRelease;
+        }
+
+        public T Get()
+        {
+            T element;
+            if (m_Stack.Count == 0)
+            {
+                element = new T();
+                countAll++;
+            }
+            else
+            {
+                element = m_Stack.Pop();
+            }
+            if (m_ActionOnGet != null)
+                m_ActionOnGet(element);
+            return element;
+        }
+
+        public void Release(T element)
+        {
+            if (m_Stack.Count > 0 && ReferenceEquals(m_Stack.Peek(), element))
+                Debug.LogError("Internal error. Trying to destroy object that is already released to pool.");
+            if (m_ActionOnRelease != null)
+                m_ActionOnRelease(element);
+            m_Stack.Push(element);
+        }
+    }
+}