title: Access appsettings.json from .NET 4.5.2 project
body: <p>I have two projects, a 1.1.0 ASP.NET Core project and a reference to a 4.5.2 project.</p>
  
  <p>I want to get values from the appsettings.json file to my 4.5.2 project. The appsettings.json file is in the core project.</p>
  
  <p>Tried this from my 4.5.2 project with no luck:</p>
  
  <pre><code>var mailServer = ConfigurationManager.AppSettings["MailServer"];
  </code></pre>
  
  <p>How can I access the values from my 4.5.2 project?</p>