fix https://github.com/kataras/iris/issues/1713 and add a simple usage example of the 'RemoveHandler'

_examples/routing/remove-handler/main_test.go

@@ -0,0 +1,14 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/kataras/iris/v12/httptest"
+)
+
+func TestSimpleRouteRemoveHandler(t *testing.T) {
+	app := newApp()
+	e := httptest.New(t, app)
+
+	e.GET("/api/users").Expect().Status(httptest.StatusOK).Body().Equal("OK")
+}