title: External AppSettings file does not work for linked files
body: <p>I have a series of MVC projects (20+) in the same solution. Some of them need to share the same values for a large number of app-settings. </p>
  
  <p>I would like to maintain these in one common location (say "appSettings.config") in a parent directory to the relevant projects for ease of maintenance, bringing the file into web.config via the file attribute on the <code>appSettings</code> tag. </p>
  
  <p>To bring the file into each project, I can use <code>Add &gt; Existing Item...</code> and this all works, but not if I select <code>Add As Link</code> when I add the existing item. Without selecting add-as-link, the file is merely copied, and the values between the 2 files are not kept in sync, defeating my purpose.</p>
  
  <p>Is there a way to get this to work with a linked appSettings.config file?</p>