[WIP] update for AngularDart 1.x

@kwalrath could you please review when you are available.

/ref https://github.com/angular/angular.dart.tutorial/pull/131
I'd change this to put the ternary info outside the parentheses, and clarify what the ternary operator is. Maybe:

    No control flow statements are allowed (no ifs or loops, for example), but the ternary operator (?:) <em>is</em> allowed.