update to v1.3.4

1. add datagrid style
2. improve the numericupdown
3. add checkbox style
4. add listbox demo
5. add treeview demo
6. add border demo
7. remove angle property of iconelement
8. add menu demo

HandyControlDemo/Data/Model/DemoDataModel.cs

@@ -0,0 +1,20 @@
+using System.Collections.Generic;
+
+// ReSharper disable once CheckNamespace
+namespace HandyControlDemo.Data
+{
+    public class DemoDataModel
+    {
+        public int Index { get; set; }
+
+        public string Name { get; set; }
+
+        public bool IsSelected { get; set; }
+
+        public string Remark { get; set; }
+
+        public DemoType Type { get; set; }
+
+        public List<DemoDataModel> DataList { get; set; }
+    }
+}