整理代码结构，支持Package Manager添加

Demo/Runtime/Demo50_Scatter.cs

@@ -0,0 +1,38 @@
+/******************************************/
+/*                                        */
+/*     Copyright (c) 2018 monitor1394     */
+/*     https://github.com/monitor1394     */
+/*                                        */
+/******************************************/
+
+using System.Collections.Generic;
+using UnityEngine;
+
+namespace XCharts
+{
+    [DisallowMultipleComponent]
+    [ExecuteInEditMode]
+    public class Demo50_Scatter : MonoBehaviour
+    {
+        private ScatterChart chart;
+
+        void Awake()
+        {
+            chart = gameObject.GetComponent<ScatterChart>();
+            if (chart == null) return;
+            chart.series.SetSerieSymbolSizeCallback(SymbolSize, SymbolSelectedSize);
+        }
+
+        float SymbolSize(List<float> data)
+        {
+            //return Mathf.Clamp(data[1] * 10,1,100);
+            return (float)(Mathf.Sqrt(data[2]) / 6e2);
+        }
+
+        float SymbolSelectedSize(List<float> data)
+        {
+            //return Mathf.Clamp(data[1] * 10,1,100);
+            return (float)(Mathf.Sqrt(data[2]) / 5e2);
+        }
+    }
+}