Full support of the http.FileSystem on all view engines as requested at #1575

Also, the HandleDir accepts both string and http.FileSystem (interface{}) (like the view's fs)

view/pug.go

@@ -2,9 +2,6 @@ package view
 
 import (
 	"bytes"
-	"io/ioutil"
-	"path"
-	"strings"
 
 	"github.com/iris-contrib/jade"
 )
@@ -16,26 +13,23 @@ import (
 //
 // Read more about the Jade Go Parser: https://github.com/Joker/jade
 //
+// Usage:
+// Pug("./views", ".pug") or
+// Pug(iris.Dir("./views"), ".pug") or
+// Pug(AssetFile(), ".pug") for embedded data.
+//
 // Examples:
 // https://github.com/kataras/iris/tree/master/_examples/view/template_pug_0
 // https://github.com/kataras/iris/tree/master/_examples/view/template_pug_1
 // https://github.com/kataras/iris/tree/master/_examples/view/template_pug_2
 // https://github.com/kataras/iris/tree/master/_examples/view/template_pug_3
-func Pug(directory, extension string) *HTMLEngine {
-	s := HTML(directory, extension)
+func Pug(fs interface{}, extension string) *HTMLEngine {
+	s := HTML(fs, extension)
 
 	s.middleware = func(name string, text []byte) (contents string, err error) {
-		name = path.Join(path.Clean(directory), name)
 		tmpl := jade.New(name)
 		tmpl.ReadFunc = func(name string) ([]byte, error) {
-			if !strings.HasPrefix(path.Clean(name), path.Clean(directory)) {
-				name = path.Join(directory, name)
-			}
-
-			if s.assetFn != nil {
-				return s.assetFn(name)
-			}
-			return ioutil.ReadFile(name)
+			return asset(s.fs, name)
 		}
 
 		// Fixes: https://github.com/kataras/iris/issues/1450
@@ -43,7 +37,6 @@ func Pug(directory, extension string) *HTMLEngine {
 		// And Also able to use relative paths on "extends" and "include" directives:
 		// e.g. instead of extends "templates/layout.pug" we use "layout.pug"
 		// so contents of templates are independent of their root location.
-
 		exec, err := tmpl.Parse(text)
 		if err != nil {
 			return