WebMatrix curated feed should also hide packages depending on packages that require Powershell

[xavierdecoster]

Example: query for "glimpse".

The Glimpse.Core package uses powershell and isn't shown.
However, quite a few dependent plugin packages that don't use powershell are listed while useless.

[analogrelay]

There may be a recent fix that is supposed to solve this. We'll take another look though. It could also be that data preceding that fix is broken.

[claycompton]

I can reproduce this in WebMatrix 3 using the curated feed currently in production.

To repro:

1. Launch WebMatrix 3
2. Create a new site based on the Empty Site template.
3. Launch the NuGet window in WebMatrix 3.
4. Check that "WebMatrix Package Source" is selected in the lower-left dropdown. Select it if it isn't.
5. Search for "glimpse". A list of packages will be returned, nost of which have a dependency on the Glimpse package.
6. Attempt to install NHibernate.Glimpse. Installation will fail with the following error:

An error occurred.

Unable to resolve dependency 'Glimpse (≥ 1.2.0)'.

System.InvalidOperationException: Unable to resolve dependency 'Glimpse (≥ 1.2.0)'.
at NuGet.InstallWalker.OnDependencyResolveError(PackageDependency dependency)
at NuGet.PackageWalker.Walk(IPackage package)
at NuGet.InstallWalker.ResolveOperations(IPackage package)
at Microsoft.WebMatrix.NuGet.NuGetPackageManager.FindDependenciesToBeInstalled(IPackage package)
at Microsoft.WebMatrix.NuGet.PackageViewModel.DetermineDependencies()
at Microsoft.WebMatrix.NuGet.PackageViewModel.b__2()
at System.Lazy1.CreateValue() at System.Lazy1.LazyInitValue()
at System.Lazy1.get_Value() at Microsoft.WebMatrix.NuGet.PackageViewModel.get_Dependencies() at Microsoft.WebMatrix.NuGet.NuGetViewModel.<ShowLicensePage>b__8() at System.Threading.Tasks.Task1.InnerInvoke()
at System.Threading.Tasks.Task.Execute()

[analogrelay]

Merged in to #1670