add 'Context.Register/RemoveDependency' for registering dependencies for next handler in the chain from a common iris handler in serve-time

And also, add a Configuration.FireEmptyFormError if end-dev wants to receive an iris.ErrEmptyForm error on missing form data on 'Context.ReadForm/ReadBody'


Former-commit-id: a2713bec77375b2908f1f066a46be4f19e6b7a61

_examples/README.md

@@ -164,6 +164,7 @@
         * [Middleware](dependency-injection/basic/middleware/main.go)
     * [Sessions](dependency-injection/sessions/main.go)
     * [Smart Contract](dependency-injection/smart-contract/main.go)
+    * [JWT](dependency-injection/jwt/main.go)
 * MVC
     * [Overview - Repository and Service layers](mvc/overview)
     * [Login - Repository and Service layers](mvc/login)

_examples/dependency-injection/jwt/main.go

@@ -37,10 +37,13 @@ func register(api *iris.APIContainer) {
 	// 		ctx.StopWithStatus(iris.StatusUnauthorized)
 	// 		return nil
 	// 	}
-
+	//
 	// 	token := j.Get(ctx)
 	// 	return token
 	// })
+	// ^ You can do the same with MVC too, as the container is shared and works
+	// the same way in both functions-as-handlers and structs-as-controllers.
+	//
 	// api.Get("/", verifiedWithBindedTokenPage)
 }