Added UserControl.

Perspex.Controls/Perspex.Controls.csproj

@@ -85,6 +85,7 @@
     <Compile Include="Primitives\Thumb.cs" />
     <Compile Include="RequestBringIntoViewEventArgs.cs" />
     <Compile Include="Shapes\Ellipse.cs" />
+    <Compile Include="UserControl.cs" />
     <Compile Include="Templates\TemplateExtensions.cs" />
     <Compile Include="TextWrapping.cs" />
     <Compile Include="Utils\StringUtils.cs" />

Perspex.Controls/UserControl.cs

@@ -0,0 +1,19 @@
+// -----------------------------------------------------------------------
+// <copyright file="UserControl.cs" company="Steven Kirk">
+// Copyright 2015 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.Controls
+{
+    using System;
+    using Perspex.Styling;
+
+    public class UserControl : ContentControl, IStyleable
+    {
+        Type IStyleable.StyleKey
+        {
+            get { return typeof(ContentControl); }
+        }
+    }
+}