Added Separator style to default theme

src/Perspex.Themes.Default/DefaultTheme.paml

@@ -15,6 +15,7 @@
   <StyleInclude Source="resource://application/Perspex.Themes.Default/Perspex.Themes.Default.PopupRoot.paml"/>
   <StyleInclude Source="resource://application/Perspex.Themes.Default/Perspex.Themes.Default.ProgressBar.paml"/>
   <StyleInclude Source="resource://application/Perspex.Themes.Default/Perspex.Themes.Default.RadioButton.paml"/>
+  <StyleInclude Source="resource://application/Perspex.Themes.Default/Perspex.Themes.Default.Separator.paml"/>
   <StyleInclude Source="resource://application/Perspex.Themes.Default/Perspex.Themes.Default.ScrollBar.paml"/>
   <StyleInclude Source="resource://application/Perspex.Themes.Default/Perspex.Themes.Default.ScrollViewer.paml"/>
   <StyleInclude Source="resource://application/Perspex.Themes.Default/Perspex.Themes.Default.TabControl.paml"/>

src/Perspex.Themes.Default/Perspex.Themes.Default.csproj

@@ -180,6 +180,9 @@
     <EmbeddedResource Include="DefaultTheme.paml">
       <SubType>Designer</SubType>
     </EmbeddedResource>
+    <EmbeddedResource Include="Separator.paml">
+      <SubType>Designer</SubType>
+    </EmbeddedResource>
   </ItemGroup>
   <Import Project="$(MSBuildExtensionsPath32)\Microsoft\Portable\$(TargetFrameworkVersion)\Microsoft.Portable.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 

src/Perspex.Themes.Default/Separator.paml

@@ -0,0 +1,7 @@
+<Style xmlns="https://github.com/perspex" Selector="Separator">
+    <Setter Property="Template">
+        <ControlTemplate>
+            <Rectangle Fill="#ffd7d7d7" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" IsHitTestVisible="False" Height="1" Margin="29,1,0,1"/>
+        </ControlTemplate>
+    </Setter>
+</Style>