GRPC Java for Android

[wingoku]

Hi @saturnism, your project has been really helpful in getting up and running with GRPC java. It'd be amazing if you can make a template Android project to provide us novices guidelines to adapt GRPC for Android. I've already tried GRPC-Java from official GRPC repo but it fails to compile for some reason. Anyways looking forward to your Sample Android app. :)

[shuza]

I have added a simple android client application and waiting for the approval of pull request. If it is accepted, an android example will be added.