refactor: export core APIs from angular2/core

This change moves many APIs to the angular2/core export.

This change also automatically adds FORM_BINDINGS in
the application root injector.

BREAKING CHANGE:
    Many dependencies that were previously exported from specific
    APIs are now exported from angular2/core. Affected exports, which
    should now be included from angular2/core include:

    angular2/forms
    angular2/di
    angular2/directives
    angular2/change_detection
    angular2/bootstrap (except for dart users)
    angular2/render
    angular2/metadata
    angular2/debug
    angular2/pipes
Closes #3977

modules/angular2/src/core/bootstrap.dart

@@ -0,0 +1,21 @@
+library angular2.src.core.bootstrap;
+
+import 'dart:async';
+
+import 'application_ref.dart';
+import 'package:angular2/src/core/reflection/reflection.dart' show reflector;
+import 'package:angular2/src/core/reflection/reflection_capabilities.dart'
+    show ReflectionCapabilities;
+import 'application_common.dart';
+
+/// Starts an application from a root component. This implementation uses
+/// mirrors. Angular 2 transformer automatically replaces this method with a
+/// static implementation (see `application_static.dart`) that does not use
+/// mirrors and produces a faster and more compact JS code.
+///
+/// See [commonBootstrap] for detailed documentation.
+Future<ApplicationRef> bootstrap(Type appComponentType,
+    [List componentInjectableBindings]) {
+  reflector.reflectionCapabilities = new ReflectionCapabilities();
+  return commonBootstrap(appComponentType, componentInjectableBindings);
+}