method
AddReferenceToCodeDirectoryEx
Microsoft.VisualStudio.LanguageServices.CSharp.ProjectSystemShim.Interop.ICSharpVenusProjectSite.AddReferenceToCodeDirectoryEx(System.String, Microsoft.VisualStudio.LanguageServices.CSharp.ProjectSystemShim.Interop.ICSharpProjectRoot, Microsoft.VisualStudio.LanguageServices.CSharp.ProjectSystemShim.Interop.CompilerOptions)