Remove WebListener and WebSockets from sample due to dependencies.

samples/SampleApp/Microsoft.AspNet.Hosting.ini

@@ -1,3 +1,3 @@
 
-Server = Microsoft.AspNet.Server.WebListener
+Server = Kestrel
 Server.Urls = http://localhost:5000/

samples/SampleApp/Startup.cs

@@ -11,8 +11,6 @@ namespace SampleApp
     {
         public void Configure(IApplicationBuilder app)
         {
-            app.UseWebSockets();
-
             app.Run(async context =>
             {
                 Console.WriteLine("{0} {1}{2}{3}",

samples/SampleApp/project.json

@@ -1,9 +1,7 @@
 {
     "version": "1.0.0-*",
     "dependencies": {
-        "Kestrel": "1.0.0-*",
-        "Microsoft.AspNet.Server.WebListener": "1.0.0-*",
-        "Microsoft.AspNet.WebSockets.Server": "1.0.0-*"
+        "Kestrel": "1.0.0-*"
     },
     "frameworks": {
         "aspnet50": { },