Added NuGet.VisualStudioExtension.symbols.nuspec that will be used to create symbol package for the vsix.
Added NuGet.VisualStudioExtension.symbols.nuspec that will be used to create symbol package for the vsix.

AArnott/NuGet.VisualStudioExtension,csharpfritz/NuGet.VisualStudioExtension,csharpfritz/NuGet.VisualStudioExtension,AArnott/NuGet.VisualStudioExtension,csharpfritz/NuGet.VisualStudioExtension,AArnott/NuGet.VisualStudioExtension,AArnott/NuGet.VisualStudioExtension,AArnott/NuGet.VisualStudioExtension,AArnott/NuGet.VisualStudioExtension,csharpfritz/NuGet.VisualStudioExtension,csharpfritz/NuGet.VisualStudioExtension