title: Angular2 subscribe "this" is replaced by SelfSubscriber
body: <p>I have a login function in an authorization component that calls a WebAPI method to process the login.</p>
  
  <pre><code>login(username: string, password: string) {
  
      let loginRequest = &lt;ILoginRequest&gt;{};
      loginRequest.username = username;
      loginRequest.password = password;
  
      let loginUrl = this._webApiConfig.rootUrl + ':' + this._webApiConfig.serverPort + this._webApiConfig.authUrl;
  
      return this._webApiDataContext.post(loginUrl, loginRequest)
          .map(response =&gt; { return response.json(); });
  }
  </code></pre>
  
  <p>It is called by this:</p>
  
  <pre><code>this._authorization.login(this.email, this.password)
      .subscribe(this.success);
  
  success(user) {
      if (user.isAuthorized) {
  
          // Set the cookie and redirect the user to the dashboard.
          this._cookie.setCookie('auth', JSON.stringify(user), 1);
          this._router.navigate(['Dashboard']);
      }
  }
  </code></pre>
  
  <p>When it gets to the success method, 'this' has been replaced with a SafeSubscriber object.  In Angular 1, I used the ControllerAs syntax, but from what I have learned in Angular 2, I don't need to anymore?  None of the examples I have found use anything like it.  I can get it to work if I set a 'vm' variable to equal 'this', but I'm still confused as to why other examples I have seen do not need to do that.</p>
  
  <p>Thanks</p>