* Rename platform_services to platform_channel

* rename in README

* renamed tests

* update modules.xml

* Add platform_services sample

* update build.gradle to use latest scripts

* use FlutterActivity

* Updated ExampleInstrumentedTest.java and deleted FlutterPlugin.groovy

* Remove getRandom code from main.dart

* remove unused import

We now use a different approach for ios projects where the developer controls
the Xcode project file. This patch removes the old ".generated" approach in
favor of the new approach.

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.