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

core/router/route_test.go

@@ -0,0 +1,56 @@
+// white-box testing
+
+package router
+
+import (
+	"github.com/kataras/iris/macro"
+
+	"testing"
+)
+
+func TestRouteStaticPath(t *testing.T) {
+	var tests = []struct {
+		tmpl   string
+		static string
+	}{
+		{
+			tmpl:   "/files/{file:path}",
+			static: "/files",
+		},
+		{
+			tmpl:   "/path",
+			static: "/path",
+		},
+		{
+			tmpl:   "/path/segment",
+			static: "/path/segment",
+		},
+		{
+			tmpl:   "/path/segment/{n:int}",
+			static: "/path/segment",
+		},
+		{
+			tmpl:   "/path/{n:uint64}/{n:int}",
+			static: "/path",
+		},
+		{
+			tmpl:   "/path/{n:uint64}/static",
+			static: "/path",
+		},
+		{
+			tmpl:   "/{name}",
+			static: "/",
+		},
+		{
+			tmpl:   "/",
+			static: "/",
+		},
+	}
+
+	for i, tt := range tests {
+		route := Route{tmpl: macro.Template{Src: tt.tmpl}}
+		if expected, got := tt.static, route.StaticPath(); expected != got {
+			t.Fatalf("[%d:%s] expected static path to be: '%s' but got: '%s'", i, tt.tmpl, expected, got)
+		}
+	}
+}