Merge pull request #11 from sericaer/master

解决PieChart的Legend中多了serie的问题

Assets/XCharts/Scripts/UI/Internal/BaseChart_API.cs

@@ -145,7 +145,11 @@ namespace XCharts
         /// <returns>the added serie</returns>
         public virtual Serie AddSerie(string serieName, SerieType type, bool show = true)
         {
-            m_Legend.AddData(serieName);
+            if(type != SerieType.Pie)
+            {
+                m_Legend.AddData(serieName);
+            }
+            
             return m_Series.AddSerie(serieName, type);
         }