support for .NET framework 3.5

Still have bugs

Net35/HandyControlDemo_Net35/UserControl/Controls/GifImageDemoCtl.xaml

@@ -0,0 +1,11 @@
+<UserControl x:Class="HandyControlDemo.UserControl.GifImageDemoCtl"
+             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:controls="clr-namespace:HandyControl.Controls;assembly=HandyControl"
+             Background="{DynamicResource RegionBrush}">
+    <controls:GifImage x:Name="GifImageMain" Margin="32" Width="400" Height="300">
+        <controls:GifImage.Source>
+            <BitmapImage UriSource="/HandyControlDemo;component/Resources/Img/car_chase.gif"/>
+        </controls:GifImage.Source>
+    </controls:GifImage>
+</UserControl>