整理代码结构，支持Package Manager添加

Scripts/Runtime/Component/Sub/AxisSplitArea.cs

@@ -0,0 +1,58 @@
+/******************************************/
+/*                                        */
+/*     Copyright (c) 2018 monitor1394     */
+/*     https://github.com/monitor1394     */
+/*                                        */
+/******************************************/
+
+using System;
+using System.Collections.Generic;
+using UnityEngine;
+
+namespace XCharts
+{
+    /// <summary>
+    /// Split area of axis in grid area, not shown by default.
+    /// 坐标轴在 grid 区域中的分隔区域，默认不显示。
+    /// </summary>
+    [Serializable]
+    public class AxisSplitArea : SubComponent
+    {
+        [SerializeField] private bool m_Show;
+        [SerializeField] private List<Color> m_Color;
+
+        /// <summary>
+        /// Set this to true to show the splitArea.
+        /// 是否显示分隔区域。
+        /// </summary>
+        public bool show { get { return m_Show; } set { m_Show = value; } }
+        /// <summary>
+        /// Color of split area. SplitArea color could also be set in color array,
+        /// which the split lines would take as their colors in turns. 
+        /// Dark and light colors in turns are used by default.
+        /// 分隔区域颜色。分隔区域会按数组中颜色的顺序依次循环设置颜色。默认是一个深浅的间隔色。
+        /// </summary>
+        public List<Color> color { get { return m_Color; } set { m_Color = value; } }
+
+        public static AxisSplitArea defaultSplitArea
+        {
+            get
+            {
+                return new AxisSplitArea()
+                {
+                    m_Show = false,
+                    m_Color = new List<Color>(){
+                            new Color32(250,250,250,77),
+                            new Color32(200,200,200,77)
+                        }
+                };
+            }
+        }
+
+        public Color getColor(int index)
+        {
+            var i = index % color.Count;
+            return color[i];
+        }
+    }
+}