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/single-page-application/basic/main.go

@@ -20,15 +20,7 @@ func newApp() *iris.Application {
 		ctx.View("index.html")
 	})
 
-	// or just serve index.html as it is:
-	// app.Get("/{f:path}", func(ctx iris.Context) {
-	// 	ctx.ServeFile("index.html", false)
-	// })
-
-	assetHandler := app.StaticHandler("./public", false, false)
-	// as an alternative of SPA you can take a look at the /routing/dynamic-path/root-wildcard
-	// example too
-	app.SPA(assetHandler)
+	app.HandleDir("/", "./public")
 
 	return app
 }

_examples/file-server/single-page-application/embedded-single-page-application-with-other-routes/main.go

@@ -9,11 +9,21 @@ import "github.com/kataras/iris"
 
 func newApp() *iris.Application {
 	app := iris.New()
-	app.OnErrorCode(404, func(ctx iris.Context) {
+	app.OnErrorCode(iris.StatusNotFound, func(ctx iris.Context) {
 		ctx.Writef("404 not found here")
 	})
 
-	app.StaticEmbedded("/", "./public", Asset, AssetNames)
+	app.HandleDir("/", "./public", iris.DirOptions{
+		Asset:      Asset,
+		AssetInfo:  AssetInfo,
+		AssetNames: AssetNames,
+		// IndexName:  "index.html", // default.
+		// If you want to show a list of embedded files when inside a directory without an index file:
+		// ShowList:   true,
+		// DirList: func(ctx iris.Context, dirName string, f http.File) error {
+		// 	// [Optional, custom code to show the html list].
+		// }
+	})
 
 	// Note:
 	// if you want a dynamic index page then see the file-server/embedded-single-page-application

_examples/file-server/single-page-application/embedded-single-page-application/main.go

@@ -22,16 +22,11 @@ func newApp() *iris.Application {
 		ctx.View("index.html")
 	})
 
-	assetHandler := iris.StaticEmbeddedHandler("./public", Asset, AssetNames, false) // keep that false if you use the `go-bindata` tool.
-	// as an alternative of SPA you can take a look at the /routing/dynamic-path/root-wildcard
-	// example too
-	// or
-	// app.StaticEmbedded if you don't want to redirect on index.html and simple serve your SPA app (recommended).
-
-	// public/index.html is a dynamic view, it's handlded by root,
-	// and we don't want to be visible as a raw data, so we will
-	// the return value of `app.SPA` to modify the `IndexNames` by;
-	app.SPA(assetHandler).AddIndexName("index.html")
+	app.HandleDir("/", "./public", iris.DirOptions{
+		Asset:      Asset,
+		AssetInfo:  AssetInfo,
+		AssetNames: AssetNames,
+	})
 
 	return app
 }
@@ -45,11 +40,3 @@ func main() {
 	// http://localhost:8080/css/main.css
 	app.Run(iris.Addr(":8080"))
 }
-
-// Note that app.Use/UseGlobal/Done will be executed
-// only to the registered routes like our index (app.Get("/", ..)).
-// The file server is clean, but you can still add middleware to that by wrapping its "assetHandler".
-//
-// With this method, unlike StaticWeb("/" , "./public") which is not working by-design anymore,
-// all custom http errors and all routes are working fine with a file server that is registered
-// to the root path of the server.