Allow users to set ShowDialog when using WebAPIFactory (#239)

Author: aleab

SpotifyAPI/Web/Auth/WebApiFactory.cs

@@ -42,13 +42,14 @@ public WebAPIFactory(string redirectUrl, int listeningPort, string clientId, Sco
             _xss = xss;
         }
 
-        public Task<SpotifyWebAPI> GetWebApi()
+        public Task<SpotifyWebAPI> GetWebApi(bool showDialog = false)
         {
             var authentication = new ImplicitGrantAuth
             {
                 RedirectUri = new UriBuilder(_redirectUrl) { Port = _listeningPort }.Uri.OriginalString.TrimEnd('/'),
                 ClientId = _clientId,
                 Scope = _scope,
+                ShowDialog = showDialog,
                 State = _xss
             };