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/basic/main.go

@@ -4,38 +4,48 @@ import (
 	"github.com/kataras/iris"
 )
 
-func main() {
+func newApp() *iris.Application {
 	app := iris.New()
 
 	app.Favicon("./assets/favicon.ico")
 
-	// enable gzip, optionally:
-	// if used before the `StaticXXX` handlers then
-	// the content byte range feature is gone.
-	// recommend: turn off for large files especially
-	// when server has low memory,
-	// turn on for medium-sized files
-	// or for large-sized files if they are zipped already,
-	// i.e "zippedDir/file.gz"
-	//
-	// app.Use(iris.Gzip)
-
 	// first parameter is the request path
 	// second is the system directory
 	//
-	// app.StaticWeb("/css", "./assets/css")
-	// app.StaticWeb("/js", "./assets/js")
-	//
-	app.StaticWeb("/static", "./assets")
+	// app.HandleDir("/css", "./assets/css")
+	// app.HandleDir("/js", "./assets/js")
 
+	app.HandleDir("/static", "./assets", iris.DirOptions{
+		// Defaults to "/index.html", if request path is ending with **/*/$IndexName
+		// then it redirects to **/*(/) which another handler is handling it,
+		// that another handler, called index handler, is auto-registered by the framework
+		// if end developer does not managed to handle it by hand.
+		IndexName: "/index.html",
+		// When files should served under compression.
+		Gzip: false,
+		// List the files inside the current requested directory if `IndexName` not found.
+		ShowList: false,
+		// If `ShowList` is true then this function will be used instead of the default one to show the list of files of a current requested directory(dir).
+		// DirList: func(ctx context.Context, dirName string, dir http.File) error { ... }
+		//
+		// Optional validator that loops through each requested resource.
+		// AssetValidator:  func(ctx iris.Context, name string) bool { ... }
+	})
+
+	// You can also register any index handler manually, order of registration does not matter:
+	// app.Get("/static", [...custom middleware...], func(ctx iris.Context) {
+	//  [...custom code...]
+	// 	ctx.ServeFile("./assets/index.html", false)
+	// })
+
+	// http://localhost:8080/static
 	// http://localhost:8080/static/css/main.css
 	// http://localhost:8080/static/js/jquery-2.1.1.js
 	// http://localhost:8080/static/favicon.ico
-	app.Run(iris.Addr(":8080"))
-
-	// Note:
-	// Routing doesn't allows something .StaticWeb("/", "./assets")
-	//
-	// To see how you can wrap the router in order to achieve
-	// wildcard on root path, see "single-page-application".
+	return app
+}
+
+func main() {
+	app := newApp()
+	app.Run(iris.Addr(":8080"))
 }