add CircleProgressBar

thanks to @ghost1372 suggestion

HandyControlDemo/UserControl/Controls/CircleProgressBarDemoCtl.xaml

@@ -0,0 +1,16 @@
+<UserControl x:Class="HandyControlDemo.UserControl.CircleProgressBarDemoCtl"
+             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:TransitioningContentControl>
+        <StackPanel Orientation="Horizontal" Margin="32">
+            <controls:CircleProgressBar Value="50"/>
+            <controls:CircleProgressBar Value="80" FontSize="30" Margin="16,0,0,0"/>
+            <controls:CircleProgressBar Value="10" Margin="16,0,0,0" ShowText="False" Width="20" Height="20" ArcThickness="2" Style="{StaticResource ProgressBarSuccessCircle}"/>
+            <controls:CircleProgressBar Value="20" Margin="16,0,0,0" ShowText="False" Width="30" Height="30" ArcThickness="6" Style="{StaticResource ProgressBarInfoCircle}"/>
+            <controls:CircleProgressBar Value="40" Margin="16,0,0,0" ShowText="False" Width="40" Height="40" ArcThickness="10" Style="{StaticResource ProgressBarWarningCircle}"/>
+            <controls:CircleProgressBar Value="80" Margin="16,0,0,0" Width="50" Height="50" Style="{StaticResource ProgressBarDangerCircle}"/>
+        </StackPanel>
+    </controls:TransitioningContentControl>
+</UserControl>

HandyControlDemo/UserControl/Controls/CircleProgressBarDemoCtl.xaml.cs

@@ -0,0 +1,11 @@
+// ReSharper disable once CheckNamespace
+namespace HandyControlDemo.UserControl
+{
+    public partial class CircleProgressBarDemoCtl
+    {
+        public CircleProgressBarDemoCtl()
+        {
+            InitializeComponent();
+        }
+    }
+}