重构LineChart和BarChart，移除Line和Bar组件，参数统一放到Serie中配置。

Scripts/UI/Internal/BaseChart_API.cs

@@ -73,6 +73,13 @@ namespace XCharts
             set { m_MaxCacheDataNumber = value; if (m_MaxCacheDataNumber < 0) m_MaxCacheDataNumber = 0; }
         }
 
+        /// <summary>
+        /// the smooth line chart style.
+        /// 平滑折线图的平滑系数。
+        /// </summary>
+        /// <value></value>
+        public float lineSmoothStyle { get { return m_LineSmoothStyle; } set { m_LineSmoothStyle = value; } }
+        
         /// <summary>
         /// Set the size of chart.
         /// 设置图表的大小。