Forms 5.0 updates. (xamarin#686)

* Use RadioButtonGroup AP.

* Add FlyoutContent example.

Author: davidbritch

UserInterface/RadioButtonDemos/RadioButtonDemos/GroupedRadioButtonsPageCode.cs

@@ -35,8 +35,8 @@ public GroupedRadioButtonsPageCode()
                 Children = { appleRadioButton, bananaRadioButton, pineappleRadioButton, otherFruitRadioButton }
             };
 
-            // All of the RadioButtons in this StackLayout will automatically be given the GroupName 'fruits`.
-            fruitStackLayout.SetValue(RadioButtonGroup.GroupNameProperty, "fruits");
+            // All of the RadioButtons in this StackLayout will automatically be given the GroupName 'fruits'.
+            RadioButtonGroup.SetGroupName(fruitStackLayout, "fruits");
 
             Title = "Grouped RadioButtons demo (code)";
             Content = new StackLayout

UserInterface/Xaminals/Xaminals/AppShell.xaml

@@ -5,6 +5,7 @@
        xmlns:sys="clr-namespace:System;assembly=netstandard"
        xmlns:views="clr-namespace:Xaminals.Views"
        x:Class="Xaminals.AppShell"
+       x:Name="shell"
        FlyoutBackgroundImage="photo.jpg"
        FlyoutBackgroundImageAspect="AspectFill"
        FlyoutHeaderBehavior="CollapseOnScroll">
@@ -98,6 +99,40 @@
         </DataTemplate>
     </Shell.FlyoutFooterTemplate>-->
 
+    <!-- FlyoutContent -->
+    <!-- Not required, just an example -->
+    <!--<Shell.FlyoutContent>
+        <CollectionView BindingContext="{x:Reference shell}"
+                        IsGrouped="True"
+                        ItemsSource="{Binding FlyoutItems}">
+            <CollectionView.ItemTemplate>
+                <DataTemplate>
+                    <Label Text="{Binding Title}"
+                           TextColor="White"
+                           FontSize="Large" />
+                </DataTemplate>
+            </CollectionView.ItemTemplate>
+        </CollectionView>
+    </Shell.FlyoutContent>-->
+
+    <!-- Template for FlyoutContent -->
+    <!-- Not required, just an example -->
+    <!--<Shell.FlyoutContentTemplate>
+        <DataTemplate>
+            <CollectionView BindingContext="{x:Reference shell}"
+                            IsGrouped="True"
+                            ItemsSource="{Binding FlyoutItems}">
+                <CollectionView.ItemTemplate>
+                    <DataTemplate>
+                        <Label Text="{Binding Title}"
+                               TextColor="White"
+                               FontSize="Large" />
+                    </DataTemplate>
+                </CollectionView.ItemTemplate>
+            </CollectionView>
+        </DataTemplate>
+    </Shell.FlyoutContentTemplate>-->
+
     <!-- Template each FlyoutItem -->
     <!--    <Shell.ItemTemplate>
         <DataTemplate>