add PropertyGrid Demo

src/Shared/HandyControl_Shared/Themes/Styles/PropertyGrid.xaml

@@ -0,0 +1,11 @@
+<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+                    xmlns:controls="clr-namespace:HandyControl.Controls"
+                    xmlns:themes="clr-namespace:HandyControl.Themes">
+    
+    <ResourceDictionary.MergedDictionaries>
+        <themes:SharedResourceDictionary Source="pack://application:,,,/HandyControl;component/Themes/Styles/Base/PropertyGridBaseStyle.xaml"/>
+    </ResourceDictionary.MergedDictionaries>
+
+    <Style BasedOn="{StaticResource PropertyGridBaseStyle}" TargetType="controls:Badge"/>
+
+</ResourceDictionary>