Support to Android Studio 2.3

[erikjhordan-rey]

Hi @riggaroo Rebecca ! First of all, thanks for your contribution Good job!

Is not an issue rather it is something like an improvement for developers who use a stable android studio version like 2.3 and wants compile this project out of android studio 3.0 preview.

I propose create another branch with two little changes to run this project in AS 2.3
(We are not all so risky to use the Android Studio Previews ;) )

  defaultConfig {
      ....
        //jackOptions is deprecated in android Studio 3.0 but this is for educational purposes
        // to compile this project in android studio 2.3 stable version.
        jackOptions {
            enabled true
        }
    } 

buildscript {
    dependencies {
        classpath 'com.android.tools.build:gradle:2.3.2'
    }

It would also be nice if you add on readme file the project only works in Android Studio 3.0 preview.

[riggaroo]

Thanks for the suggestion. I've created a new branch for stable version of AS 👍