add watch page

Program.cs

@@ -153,6 +153,12 @@ namespace youtube_downloader
                 string json = JsonConvert.SerializeObject(Server.Functions.Downloader.GetProgress());
                 rp.AsText(json, "application/json");
             });
+            Route.Add("/api/Watch/{VideoId}", (rq, rp, args) =>
+            {
+                var txt = Templating.RenderFile(Path.Combine(webSitePath, "watch_page.thtml"), args); //populate template
+                rp.AsText(txt);
+            });
+
             Route.Add("/api/Redownload", (rq, rp, args) =>
             {
                 foreach (var item in Directory.GetFiles(Server.Functions.Downloader.DL.GetPath(true, "Info"), "*.json"))