anchor.diff:  :marked
     ## Appendices
     The balance of this chapter is a set of appendices that
  -  elaborate some of the points we covered quickly above.
  +  elaborate on some of the points we covered quickly above.
     
     There is no essential material here. Continued reading is for the curious.
     
  
positive.code:     * We iterate development faster because we only re-compile changed files.
      We notice the difference as soon as the app grows beyond a handful of files.
      
      * pre-compilation fits into a continuous integration process of build, test, deploy.
  :marked
    The `System.import` call tells SystemJS to import the `boot` file 
    (`boot.js` ... after transpiling `boot.ts`, remember?).
  
negative.code:   this library most of the time. It's pretty "core" if we're always writing for a browser.
      
    But it is possible to load a component in a different enviroment. 
    We might load it on a mobile device with [Apache Cordova](https://cordova.apache.org/).
    We might wish to render the first page of our application on the server 
    to improve launch performance or facilitate 
    [SEO](http://static.googleusercontent.com/media/www.google.com/en//webmasters/docs/search-engine-optimization-starter-guide.pdf).
  