feat(dart/transform): Add a di transformer

Add a transformer for `di` which generates `.ng_deps.dart` files for all
`.dart` files it is run on. These `.ng_deps.dart` files register
metadata for any `@Injectable` classes.

Fix unit tests for changes introduced by the di transformer.

When using `pub (build|serve) --mode=ngstatic`, we will also generate
getters and setters, parse templates, and remove import of `dart:mirrors`
in the Angular transform. Because this is still relatively immature, we
use the mode to keep it opt-in for now.

Closes #700

modules/angular2/test/transform/directive_processor/parameter_metadata/expected/soup.ng_deps.dart

@@ -1,4 +1,4 @@
-library dinner.soup;
+library dinner.soup.ng_deps.dart;
 
 import 'soup.dart';
 import 'package:angular2/src/core/annotations/annotations.dart';