This requires delicate handling of type definitions which collide, because
we use TypeScript-provided lib.d.ts for --target=es5 and lib.es6.d.ts for
--target=es6.
We need to include our polyfill typings only in the --target=es5 case,
and the usages have to be consistent with lib.es6.d.ts.
Also starting with this change we now typecheck additional modules,
so this fixes a bunch of wrong typings which were never checked before.
Fixes#3178
BREAKING CHANGES:
Dart applications and TypeScript applications meant to transpile to Dart must now
import `package:angular2/bootstrap.dart` instead of `package:angular2/angular2.dart`
in their bootstrap code. `package:angular2/angular2.dart` no longer export the
bootstrap function. The transformer rewrites imports of `bootstrap.dart` and calls
to `bootstrap` to `bootstrap_static.dart` and `bootstrapStatic` respectively.
