Update vendor for Pug (Jade) Parser and add Iris + Pug examples in the _examples/view folder, relative to https://github.com/kataras/iris/issues/1003

Former-commit-id: e26a5701e00ec055f3bcf693c1980c7d22147310

_examples/view/template_pug_0/templates/index.pug

@@ -0,0 +1,25 @@
+mixin withGo
+  | Generating Go html/template output.
+
+doctype html
+html(lang="en")
+  head
+    title= .pageTitle
+    script(type='text/javascript').
+      if (foo) {
+         bar(1 + 5)
+      }
+  body
+    h1 Jade - template engine
+    #container.col
+      if .youAreUsingJade
+        p {{ greet "iris user" }} <!-- execute template funcs -->
+        p You are amazing!
+      else
+        p Get on it!
+      p.
+        Jade is #[a(terse)] and simple
+        templating language with a
+        #[strong focus] on performance
+        and powerful features.
+      + withGo