support for .NET framework 3.5

Still have bugs

Net35/HandyControl_Net35/Properties/AssemblyInfo.cs

@@ -0,0 +1,13 @@
+using System.Reflection;
+using System.Runtime.InteropServices;
+
+[assembly: AssemblyTitle("HandyControl")]
+[assembly: AssemblyDescription("Contains some commonly used simple WPF controls")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("HandyControl")]
+[assembly: AssemblyCopyright("Copyright © NaBian 2018-2019")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+[assembly: ComVisible(false)]
+[assembly: AssemblyVersion("1.5.2.*")]