regenerate book (& update build script pubspec.lock)

staged under https://book-dot-dart-lang.appspot.com/docs/dart-up-and-running/

The old dartdoc page (book-dot-dart-lang.appspot.com/docs/dart-up-and-running/contents/ch04-tools-dartdoc.htm, which is not in the book and thus no longer generated) redirects to the new page. The dart2js situation is handled differently... The page itself just links to the new page. Perhaps I should delete the dart2js page too, even though that'd be different from the book?

R=shaza@google.com

Review URL: https://chromiumcodereview.appspot.com/196023006