增加A2WToolBox工具集，增加Launch场景核LaunchPanel

Assets/A2WToolBox/Runtime/Singleton/SceneSingleton.cs

@@ -0,0 +1,25 @@
+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+
+namespace A2W
+{
+    public class SceneSingleton<T> : MonoBehaviour where T : MonoBehaviour
+    {
+        public static T instance
+        {
+            get
+            {
+                if (_instance == null)
+                {
+                    _instance = FindObjectOfType<T>();
+                }
+                return _instance;
+            }
+        }
+        private static T _instance;
+
+    }
+}
+
+