anchor.diff:    Let's begin with a few core concepts of the Component Router.
     Then we can explore the details through a sequence of examples.
     ### Setup
  -  The Component Router is an optional service that presents a particular component view for a given URL.
  +  The Angular Component Router is an optional service that presents a particular component view for a given URL.
     It is not part of the Angular 2 core. It is in its own library 
     within the Angular npm bundle.
     We make it available by loading its script in our `index.html`, after
  
positive.code:   tr
      td <code>@RouteConfig</code>
      td.
        Configures a router with <code>RouteDefinitions</code>, each mapping a URL path to a Component.
    tr
      td <code>RouteDefinition</code>
      td.
        Defines how the router should navigate to a Component based on a URL pattern.
    tr
      td <code>Route</code>
      td.
  
negative.code: :marked
    ### Configuration
    When the browser's URL changes, the router looks for a corresponding **`RouteDefinition`**
    from which it can determine the component to display.
  
    A new router has no route definitions. We have to configure it.
    The preferred way to configure the router is with a **`@RouteConfig`** [decorator](glossary.html#decorator)
  