title: Could not load file or assembly 'System.Web.Http,' - when Adding one project to another solution
body: <p>This was all working fine when I had two separate solutions - a webApi solution and a MVC solution.  I'm trying to pull the MVC solution into the WebAPI one to consolodate everything but I keep getting random reference errors.  The latest is: </p>
  
  <blockquote>
    <p>Could not load file or assembly 'System.Web.Http, Version=4.0.0.0,
    Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its
    dependencies. The located assembly's manifest definition does not
    match the assembly reference.</p>
  </blockquote>
  
  <p>I've searched and searched but I can't find a solution.  I've deleted my bin, rebuilt, uninstalled MVC, reinstalled it, made sure "Specific version" is set to false... I'm stuck and frustrated.  What else could be causing this?  </p>
  
  <p>I get the error when I try to load the MVC application.  </p>