Add AngularDart example

Add an example app to the labs for AngularDart without routing.

AngularDart is heavily inspired by AngularJS and is supercharged for Dart. Core
Angular features such as directives, data binding, and dependency injection, are
all there, and they've taken advantage of Dart's features like metadata, types,
and classes to feel natural for Dart developers. AngularDart is also the first
version of Angular to be built on emerging web standards like Shadow DOM.
AngularDart: Add compiled JavaScript + SourceMap

closes #741