Add UIX source samples from Zune Software v2.1

test/2.1/POPUP.UIX

@@ -0,0 +1,43 @@
+<!-- Copyright (C) Microsoft Corporation. All rights reserved. -->
+<UIX 
+  xmlns="http://schemas.microsoft.com/2007/uix"
+  xmlns:zune="assembly://ZuneShell/ZuneUI" 
+  xmlns:me="Me">
+  
+  
+  
+  
+
+  <Class Name="Popup">
+    <Properties>
+      <zune:PopupHelper Name="Helper" />
+      <PopupLayoutInput Name="LayoutInput" />
+      <String Name="PopupUI" String="{null}"/>
+      <Object Name="Model" Object="{null}"/>
+    </Properties>
+  </Class>
+
+  <UI Name="PopupHost">
+    <Properties>
+      <me:Popup Name="Popup" Popup="$Required" />
+    </Properties>
+
+    <Scripts>
+      <Script>
+        Host.RequestSource(Popup.PopupUI);
+      </Script>
+    </Scripts>
+
+    <Content>
+      <me:PopupUI Name="Host" Popup="{Popup}" Model="{Popup.Model}"/>
+    </Content>
+  </UI>
+
+  <UI Name="PopupUI">
+    <Properties>
+      <me:Popup Name="Popup" Popup="$Required"/>
+      <Object Name="Model" Object="$Required"/>
+    </Properties>
+  </UI>
+
+</UIX>