create the new FileServer and HandleDir, deprecate the rest APIBuilder/Party static methods and more

relative: https://github.com/kataras/iris/issues/1283 and removing pongo2 from vendor: https://github.com/kataras/iris/issues/1284

Former-commit-id: 3ec57b349f99faca2b8e36d9f7252db0b6ea080d

_examples/file-server/embedding-files-into-app/main.go

@@ -14,8 +14,14 @@ import (
 // See `file-server/embedding-gziped-files-into-app` example as well.
 func newApp() *iris.Application {
 	app := iris.New()
+	app.Logger().SetLevel("debug")
 
-	app.StaticEmbedded("/static", "./assets", Asset, AssetNames)
+	app.HandleDir("/static", "./assets", iris.DirOptions{
+		Asset:      Asset,
+		AssetInfo:  AssetInfo,
+		AssetNames: AssetNames,
+		ShowList:   true,
+	})
 
 	return app
 }

_examples/file-server/embedding-files-into-app/main_test.go

@@ -66,12 +66,21 @@ var urls = []resource{
 }
 
 // if bindata's values matches with the assets/... contents
-// and secondly if the StaticEmbedded had successfully registered
+// and secondly if the HandleDir had successfully registered
 // the routes and gave the correct response.
 func TestEmbeddingFilesIntoApp(t *testing.T) {
 	app := newApp()
 	e := httptest.New(t, app)
 
+	route := app.GetRouteReadOnly("GET/static/{file:path}")
+	if route == nil {
+		t.Fatalf("expected a route to serve embedded files")
+	}
+
+	if len(route.StaticSites()) > 0 {
+		t.Fatalf("not expected a static site, the ./assets directory or its subdirectories do not contain any index.html")
+	}
+
 	if runtime.GOOS != "windows" {
 		// remove the embedded static favicon for !windows,
 		// it should be built for unix-specific in order to be work