Add cursor trail sprites.

osu.Game.Resources/osu.Game.Resources.csproj

@@ -173,6 +173,10 @@
     <EmbeddedResource Include="Fonts\FontAwesome_4.png" />
     <EmbeddedResource Include="Fonts\FontAwesome_5.png" />
   </ItemGroup>
+  <ItemGroup>
+    <EmbeddedResource Include="Textures\Cursor\cursortrail%402x.png" />
+    <EmbeddedResource Include="Textures\Cursor\cursortrail.png" />
+  </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.