add some demos & styles

1. add window demo
2. add scrollviewer demo
3. add radiobutton style
4. fixed some bugs
5. add research project

HandyControlDemo/ViewModel/WindowDemoViewModel.cs

@@ -0,0 +1,19 @@
+using System;
+using GalaSoft.MvvmLight.CommandWpf;
+using HandyControlDemo.Tools;
+
+namespace HandyControlDemo.ViewModel
+{
+    public class WindowDemoViewModel
+    {
+        public RelayCommand<string> OpenWindowCmd => new Lazy<RelayCommand<string>>(() => new RelayCommand<string>(OpenWindow)).Value;
+
+        private void OpenWindow(string windowTag)
+        {
+            if (AssemblyHelper.CreateInternalInstance($"Window.{windowTag}") is System.Windows.Window window)
+            {
+                window.ShowDialog();
+            }
+        }
+    }
+}