Include execution assemblies in appx packaging

Author: AArnott

src/Xunit.SkippableFact.NuGet/build/Xunit.SkippableFact.props

@@ -1,10 +1,20 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="14.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
-    <None Include="$(MSBuildThisFileDirectory)Xunit.SkippableFact.*.dll">
+    <XunitSkippableFactExecutionLibs Include="$(MSBuildThisFileDirectory)Xunit.SkippableFact.*.dll"/>
+    
+    <None Include="@(XunitSkippableFactExecutionLibs)">
       <Link>%(Filename)%(Extension)</Link>
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
       <Visible>False</Visible>
     </None>
   </ItemGroup>
+
+  <Target Name="AddXunitSkippableFactExecutionLibs" AfterTargets="_ComputeAppxPackagePayload" BeforeTargets="_GenerateAppxManifest">
+    <ItemGroup>
+      <AppxPackagePayload Include="@(XunitSkippableFactExecutionLibs)">
+        <TargetPath>%(FileName)%(Extension)</TargetPath>
+      </AppxPackagePayload>
+    </ItemGroup>
+  </Target>
 </Project>