tidy the codes

src/Shared/HandyControl_Shared/Themes/Styles/Poptip.xaml

@@ -0,0 +1,12 @@
+<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+                    xmlns:controls="clr-namespace:HandyControl.Controls">
+    
+    <ResourceDictionary.MergedDictionaries>
+        <ResourceDictionary Source="Base/PoptipBaseStyle.xaml"/>
+    </ResourceDictionary.MergedDictionaries>
+
+    <Style BasedOn="{StaticResource PoptipBaseStyle}" TargetType="controls:Poptip">
+        
+    </Style>
+
+</ResourceDictionary>