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

HandyControl/HandyControl.csproj.user

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <ProjectView>ProjectFiles</ProjectView>
+  </PropertyGroup>
+</Project>