Update gRPC in C# minutes readme.

examples/csharp/helloworld/README.md

@@ -5,23 +5,16 @@ BACKGROUND
 -------------
 For this sample, we've already generated the server and client stubs from [helloworld.proto][].
 
-Example projects depend on the [Grpc](https://www.nuget.org/packages/Grpc/)
+Example projects depend on the [Grpc](https://www.nuget.org/packages/Grpc/), [Grpc.Tools](https://www.nuget.org/packages/Grpc.Tools/)
 and [Google.Protobuf](https://www.nuget.org/packages/Google.Protobuf/) NuGet packages
 which have been already added to the project for you.
 
 PREREQUISITES
 -------------
-**Windows**
-- .NET 4.5+
-- Visual Studio 2013 or 2015
 
-**Linux**
-- Mono 4.0+
-- Monodevelop 5.9+ (with NuGet plugin installed)
-
-**Mac OS X**
-- Xamarin Studio 5.9+
-- [homebrew][]
+- Windows: .NET Framework 4.5+, Visual Studio 2013 or 2015
+- Linux: Mono 4+, MonoDevelop 5.9+ (with NuGet add-in installed)
+- Mac OS X: Xamarin Studio 5.9+
 
 BUILD
 -------
@@ -56,6 +49,5 @@ Tutorial
 
 You can find a more detailed tutorial in [gRPC Basics: C#][]
 
-[homebrew]:http://brew.sh
 [helloworld.proto]:../../protos/helloworld.proto
 [gRPC Basics: C#]:http://www.grpc.io/docs/tutorials/basic/csharp.html