Add CI build badge

Add CI build badge

Author: drieseng

README.md

@@ -3,6 +3,7 @@ SSH.NET
 SSH.NET is a Secure Shell (SSH) library for .NET, optimized for parallelism.
 
 [![Version](https://img.shields.io/nuget/vpre/SSH.NET.svg)](https://www.nuget.org/packages/SSH.NET)
+[![Build status](https://ci.appveyor.com/api/projects/status/ih77qu6tap3o92gu/branch/develop?svg=true)](https://ci.appveyor.com/api/projects/status/ih77qu6tap3o92gu/branch/develop)
 
 ##Introduction
 This project was inspired by **Sharp.SSH** library which was ported from java and it seems like was not supported for quite some time. This library is a complete rewrite, without any third party dependencies, using parallelism to achieve the best performance possible.