Top 20 NuGet internalsvisibleto Packages

Adds support for InternalsVisibleTo as an ItemGroup allowing you to annotate assemblies that should be able to see internals of given assembly. Adds support for AssemblyMetadata as an ItemGroup allowing you to set assembly metadata easily through msbuild
Enables declaring 'InternalsVisibleTo' items in a .NET project file, rather than declaring them to an AssemblyInfo.cs file.
Allow to declare 'InternalsVisibleTo' in the csproj file, rather than declaring them to an AssemblyInfo.cs file.