title: angular 2 call initial function before first routing
body: <p>I have an app where i want to load all the messages from the server before actually loading the app.</p>
  
  <p>I've put the http request in my app component in OnInit.</p>
  
  <p>but I don't have a way to make the routing "wait" before fetching the first page and the application is starting with empty messages.</p>
  
  <p>Any way to do this ?</p>