* Add flutter_view sample

* Removed platform_services files

* Addressed comments

* update README.md

* Addressed comments.

This patch changes the default `flutter create` command to generate a
HelloServices-style app on iOS. As a consequence, the Atom integration now
fully works with HelloServices.

Currently this service just returns mock data, but it exercises the plumbing.

This example shows how to build a basic app using a custom Xcode project.
Future patches will bring the functionality up to par with hello_android.