add some demos & styles

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

DockContainerResearch/Controls/DockBox.cs

@@ -0,0 +1,9 @@
+using System.Windows.Controls;
+
+namespace DockBoxResearch.Controls
+{
+    public class DockBox : Control
+    {
+        
+    }
+}