View Helper "Flash Message"
Provide a view helper which allows for handling "flash messages", i.e. a short message / chunk of HTML which transports information from one action to another.
Example: the createAction() successfully creates a Thing and submits the message "Successfully created Thing." to the view helper. Then a redirect to the indexAction() is carried out. The index view contains an area which displays a flash message, if any. In this case there's one: "Sucessfully created Thing.".