support for .NET framework 3.5

Still have bugs

Net35/HandyControlDemo_Net35/UserControl/Basic/Avatar.xaml

@@ -0,0 +1,22 @@
+<UserControl x:Class="HandyControlDemo.UserControl.Avatar"
+             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
+             Margin="16"
+             Effect="{StaticResource EffectShadow5}" 
+             Cursor="Hand"
+             mc:Ignorable="d">
+    <Button Style="{StaticResource ButtonCustom}" Click="ButtonAvatar_OnClick">
+        <Border Background="{DynamicResource SecondaryRegionBrush}" CornerRadius="10">
+            <Grid>
+                <Grid.RowDefinitions>
+                    <RowDefinition/>
+                    <RowDefinition Height="Auto"/>
+                </Grid.RowDefinitions>
+                <Image Source="{Binding Source,RelativeSource={RelativeSource AncestorType=UserControl}}" Height="120" Width="120" Stretch="Uniform" Margin="10"/>
+                <TextBlock TextTrimming="CharacterEllipsis" TextWrapping="NoWrap" Margin="0,0,0,10" Grid.Row="1" Style="{StaticResource TextBlockDefault}" Text="{Binding UserName,RelativeSource={RelativeSource AncestorType=UserControl}}"></TextBlock>
+            </Grid>
+        </Border>
+    </Button>
+</UserControl>