title: ServiceStack.ServiceHost.Feature does not contain a definition for Remove
body: <p>I have referenced ServiceStack.dll ver-3.9.4 </p>
  
  <p>Included the code in AppHost.cs</p>
  
  <p>SetConfig(new EndpointHostConfig
  {</p>
  
  <p>EnableFeatures = Feature.All.Remove(Feature.Html),</p>
  
  <p>});</p>
  
  <p>I get the error below and cannot compile</p>
  
  <p>'ServiceStack.ServiceHost.Feature' does not contain a definition for 'Remove' and no extension method 'Remove' accepting a first argument of type 'ServiceStack.ServiceHost.Feature' could be found (are you missing a using directive or an assembly reference?)</p>
  
  <p>Tried including many directives and still I cannot get past this</p>
  
  <p>using Funq;</p>
  
  <p>using ServiceStack.WebHost.Endpoints;</p>
  
  <p>using ServiceStack.ServiceHost;</p>
  
  <p>using ServiceStack.WebHost.Endpoints.Support;</p>
  
  <p>using ServiceStack.Common.Support;</p>
  
  <p>using ServiceStack.Common.Extensions;</p>
  
  <p>using ServiceStack.Common.Utils;</p>
  
  <p>using ServiceStack.Common.Web;</p>
  
  <p>using ServiceStack.Logging.Support.Logging;</p>
  
  <p>using ServiceStack.CacheAccess;</p>
  
  <p>using ServiceStack.CacheAccess.Providers;</p>
  
  <p>using ServiceStack.OrmLite;</p>
  
  <p>using ServiceStack.WebHost;</p>