feat(transformers): implement initializing deferred libraries

Implement deferred libraries to work with dependency injection and other
angular codegen. This is done by not initializing the library in the parent
ng_deps file when it is declared as deferred, rewriting the import and,
chaining a future that initializes the library in any files that are using
deferred libraries which need angular codegen.

modules/angular2/test/transform/integration/list_of_types_files/expected/bar.ng_deps.dart

@@ -1,6 +1,7 @@
 library bar.ng_deps.dart;
 
 import 'bar.dart';
+export 'bar.dart';
 import 'package:angular2/src/reflection/reflection.dart' as _ngRef;
 import 'package:angular2/src/core/annotations_impl/annotations.dart';
 import 'foo.dart';

modules/angular2/test/transform/integration/simple_annotation_files/expected/bar.ng_deps.dart

@@ -1,6 +1,7 @@
 library bar.ng_deps.dart;
 
 import 'bar.dart';
+export 'bar.dart';
 import 'package:angular2/src/reflection/reflection.dart' as _ngRef;
 import 'package:angular2/src/core/annotations_impl/annotations.dart';
 

modules/angular2/test/transform/integration/simple_annotation_files/expected/index.ng_deps.dart

@@ -1,6 +1,7 @@
 library web_foo.ng_deps.dart;
 
 import 'index.dart';
+export 'index.dart';
 import 'package:angular2/src/reflection/reflection.dart' as _ngRef;
 import 'package:angular2/src/core/application.dart';
 import 'package:angular2/src/reflection/reflection.dart';

modules/angular2/test/transform/integration/synthetic_ctor_files/expected/bar.ng_deps.dart

@@ -1,6 +1,7 @@
 library bar.ng_deps.dart;
 
 import 'bar.dart';
+export 'bar.dart';
 import 'package:angular2/src/reflection/reflection.dart' as _ngRef;
 import 'package:angular2/src/core/annotations_impl/annotations.dart';
 

modules/angular2/test/transform/integration/two_annotations_files/expected/bar.ng_deps.dart

@@ -4,6 +4,7 @@ import 'package:angular2/src/change_detection/pregen_proto_change_detector.dart'
     as _gen;
 
 import 'bar.dart';
+export 'bar.dart';
 import 'package:angular2/src/reflection/reflection.dart' as _ngRef;
 import 'package:angular2/src/core/annotations_impl/annotations.dart';
 import 'package:angular2/src/core/annotations_impl/view.dart';

modules/angular2/test/transform/integration/two_deps_files/expected/bar.ng_deps.dart

@@ -1,6 +1,7 @@
 library bar.ng_deps.dart;
 
 import 'bar.dart';
+export 'bar.dart';
 import 'package:angular2/src/reflection/reflection.dart' as _ngRef;
 import 'package:angular2/src/core/annotations_impl/annotations.dart';
 import 'foo.dart' as prefix;