Updating Newtonsoft.Json to 6.0.6

We use Json.NET to parse `project.json` for ASP.NET 5 projects. They use Json.NET 6 and the main issue is that they include single-line comments in the json files which is not supported in 5.x
I did that and it put back all the redirect bindings for Json.NET 6.
I actually I know what's going on. WebAPI has a hard dependency on Newtonsoft 4.5.0.0. Looking at the Direct References below you will see `Newtonsoft.Json 4.5.0.0`. 
The reason we were using `Newtonsoft.Json 5.0.8` before and didn't have to add binding redirect is because [`Newtonsoft 5.0.8`](https://github.com/JamesNK/Newtonsoft.Json/releases/tag/5.0.8) kept assembly [version number to 4.5.0.0](https://github.com/JamesNK/Newtonsoft.Json/blob/d03963016e3d691950f19896178e6e8ea0de1b3b/Src/Newtonsoft.Json/Properties/AssemblyInfo.cs#L94-L95) which is not the case with [`Newtonsoft.Json 6.0.x`](https://github.com/JamesNK/Newtonsoft.Json/blob/master/Src/Newtonsoft.Json/Properties/AssemblyInfo.cs#L93-L94)

![image](https://cloud.githubusercontent.com/assets/645740/5273448/1bdc27d0-7a3c-11e4-99b0-b4b54b78aed9.png)